Coda 2 - <AUTHOR> http://panic.com/coda/ <comment><USER2> They seem to have defined their target user, and design around it. And I think most of us are not this target user.

I have used Coda since 1.0, but later switched to TextMate and now, Sublime Text. And eventually, I replaced all the good parts of Coda with something that wouldn't work with Coda as well:

\- I write Ruby, not PHP, and it's not one-input-file-equals-one-output-file at all. So preview is not that useful. Completion probably won't work for Ruby as well as for PHP, and so on.

\- I don't write CSS or JS anymore, and I don't think I could live without my SCSS or CoffeeScript (well, I can, but it's painful). So all the fancy CSS GUI pop-ups don't help, I have a probably even better solution in code and mixins.

\- Finally, all the UI seems to be Novice-friendly, with sidebars and tabs, while I don't even have a sidebar at all on ST2, and just use Cmd+T for opening / switching files.

Also, as for the site itself, the demo tour looks awesome (even though a bit crammed).

All the best to them! I won't be upgrading, but I think many will find Coda 2 a great improvement.

P.S. I love that they list app being "Retina-Ready" while we still don't have any retina Macs yet :)

<comment><USER3> I followed that same path of editors but ended in vim (instead of sublime) and use a number terminal tools.

Coda is really pretty and wish i could have some of my workflow.

<comment><USER4> (Sublime is gradually implementing VI commands, if anyone's interested. Look up the Vintage and VintageEx packages.)

<comment><USER3> Yes, I did notices that. Sublime is very tempting but the cost and having a workflow that I'm happy with stop me from using in a project atm.

<comment><USER5> Cost? Seriously? It's like $40.

<comment><USER6> $59; which is IMHO a totally fair price. Even if you're that strapped for cash, there's no cap on the trial so you aren't pressed for time to come up with the money.

</comment></comment></comment></comment></comment></comment><comment><USER7> Looks good but I think this is still more like iWeb than a true hacker's editor. Too much GUI. It assumes you are dealing with more-or-less the LAMP stack and basic PHP websites. Also, I feel like this is kind of another example of do one thing well vs. do a lot of things decently well. If you're depending on one single app for your terminal, MySQL GUI, CSS editor, etc... it feels like bloat. Hand-holding development. Fisher Price. I think most hackers would rather use individual tools that might be more powerful and configurable.

I don't know anyone using Coda except a friend who chickenscratches together jQuery scripts and pieces of PHP. He's not a craftsman.

Just to be clear: Panic makes some great software and they're some really talented guys. I just dislike Coda.

Just for fun: Textmate user for 5 years, have shifted to Sublime because I enjoy some of it's key commands better. They're very similar though. vim on the server.

<comment><USER8> Tools are there to make things easier. It doesn't make you any less of a developer just because you use the Refactor command rather than manually change 20 files. In fact it makes you a better developer.

No offense but I would NEVER hire anybody who subscribed to your way of thinking.

<comment><USER9> Interesting. As a hacker myself, I would be more interested in hiring (if I was in the position to hire) someone that could quickly `grep` and `sed` their entire repository for the occurrences of a function name that needed refactoring, all the while never leaving the same terminal window that Vim or Emacs was running in.

I agree with both of you though. My frontend co-workers need to constantly have that browser window open and complain about their F5 key wearing thin, while I'm lucky if I manage to remember what local domain name I assigned to Apache that points to the project I've been working on for the past 8 hours. My code tests tell me everything I need to know, and I can tell whether or not they're passing from my same terminal window.

We all use different tools, many times to solve the same problem, and on occasion we'll use the same tools to solve different problems. The wheel wasn't a breakthrough in the transportation technology only, it also sparked the mechanical revolution once someone meshed two together.

<comment><USER10> This is a false dichotomy. Knowing how to grep is essential, but that doesn't mean you must forego other convenient tools just in order to preserve your "hacker cred". Use whatever is most efficient to do a specific task.

</comment></comment></comment></comment><comment><USER11> I noticed it's nice new CSS feature only generates Webkit specific CSS[1]. That is _not_ good.

However, I think their usage of CSS3 transforms to focus on different parts of the video is pretty clever. Watching the video on its own feels rather bland in comparison.

[1] <http://i.imgur.com/rpVUw.png>

<comment><USER12> " I think their usage of CSS3 transforms to focus on different parts of the video is pretty clever. Watching the video on its own feels rather bland in comparison." It may have been clever, but it absolutely thrashes my cpu. Why didn't they just do the transforms/transitions in whatever they used to record the screencast? Coda2 looks great but using css3 like that will thrash the browser way more than building it out in Flash would have.

<comment><USER13> What browser are you using? It runs like a dream in Safari.

<comment><USER14> And therein lies the rub. Panic is hardly alone, but where once stood a legion of Mac users screaming bloody murder (and rightly so) at websites that were "Designed for IE on Windows", now there is a generation of "Works in Safari? Looks good on my iPad? Ship it!" designers and developers.

<comment><USER15> Nobody's specified the browser where CSS3 animations look bad yet. I'm not a web developer, but I use Safari, Chrome, and Firefox to varying degrees, and I don't see single-browser breakage going on.

<comment><USER14> True, unusued CPU power is "going to waste", but when an i7 950 overclocked to 3.5GHz, running of an SSD and 1600MHz memory with Chrome 18 uses 20% of CPU for a transition that's a problem (though with what is a different argument).

My point, though, was that to me it highlighted a more symptomatic issue, that a certain segment of the population, who used to rail against discrimination against their chosen platform, are more than happy to cheerlead / defend / exonerate discrimination for their chosen platform.

</comment></comment></comment></comment></comment></comment><comment><USER16> 1\. Any sufficiently complicated text editing program contains an ad hoc, informally specified, bug-ridden, slow implementation of half of vim.

2\. No new programming environment will ever satisfy advanced vim users without adding a "vim emulation" mode, thus satisfying #1. (p.s. I am a vim user)

<comment><USER17> I totally agree with #2. I'm curious whether you've tried Sublime's Vintage Mode and what things may have been slow or buggy.

I'd say my Vim skills are somewhere between novice and intermediate and feel entirely out-of-place editing text without vim bindings nearby.

<comment><USER16> BTW it was a parody of <http://en.wikipedia.org/wiki/Greenspuns_tenth_rule>

<comment><USER17> Ohhhhhhh, gotcha.

</comment></comment></comment></comment><comment><USER18> Wow, tough crowd.

This is a Dreamweaver killer for CMS themers, no need to bring Vim into the conversation.

<comment><USER19> Finally someone makes the explicit mention.

The app looks great but I think the tab interface looks really...just dumb. I don't understand why so much of my screenspace has to be filled with this obtrusive icon preview of an entire webpage (which you can't completely see), page of code (which you can't completely see), MySQL editor (which you can't comp-ok you get my point).

Otherwise looks good.

</comment></comment><comment><USER20> Looks good. TextMate remains my go-to editor (and that's not going to change, it's just not), but I've always appreciated Coda when doing WordPress work.

The new features make it look like for WordPress or other MySQL-backed CMSes, it'll be super nice.

Would love to know if they plan on doing more to get developers to create more add-ons for Coda. The community is there, but it's super small compared to TextMate, Sublime Text and even Espresso.

Still, as a rule, I buy anything Panic puts out so I'm getting this on Thursday.

ETA: I think the real brilliance here is Diet Coda for iPad. AirPreview is genius and bringing subset editing functionality to the iPad in a meaningful way is great.

<comment><USER21> > AirPreview is genius and bringing subset editing functionality to the iPad > in a meaningful way is great.

There's no editing functionality, just a preview of the page.

<comment><USER22> Yes there is, read again. AirPreview is a single feature of the portable viewer/editor for iOS.

<http://panic.com/dietcoda/>

<comment><USER21> Completely missed that, sorry.

</comment></comment></comment></comment><comment><USER23> Hm, when I clicked on the Coda tour button, it sped through the video at 2x speed. That's odd.

I feel a bit sorry for Panic. Their designs, imo, have been mimicked so much across the internet that their site now looks old and cliche. It's not their fault and it looks very nice, but because so many sites use it I just can't stand it now.

</comment><comment><USER24> Wow, looks very nice. I didn't see anything about this on the page, but is it still geared towards PHP/static/etc sites with normal non-rewritten URLs? It didn't seem to work very nicely with fancy rewritten URLs when I tried it last (for example, the preview feature doesn't work).

<comment><USER25> The demo shows PHP and the feature list mentions "Improved Ruby," although I am not sure what that means. It's been years since I used Coda and I wasn't doing a lot of hacking back then.

</comment></comment><comment><USER26> Panic markets their own software better than just about anyone in the business. I always love their new product demo sites!

<comment><USER27> Not sure I agree. I've never heard of Coda before, and the webpage doesnt really tell me what it does or why I need it. I get the impression its some sort of visual studio-like thingy for mac users?

</comment></comment><comment><USER28> I like Coda for the built in SSH support.. all my dev work is done on a dedicated dev server, I don't code anything locally.

So everyday text editors don't really work for me. I have tried remote mounting SSH and using text editors that way but its never been as smooth as Coda with the integrated file browsing.

Having a dedicated dev server is a real treat if you want to code from multiple machines and need a real robust server environment.

</comment><comment><USER29> Love coda for managing large numbers of cms installs. Use it for all my non- vim work (pair programing and more serious dev tasks just work better in vim, makes me think better). Exploring a code base works better for me in coda, the function names in the sidebar and file management, it's a nice light weight IDE. I often end up with both coda and vim going at the same time.

<comment><USER30> Yes. Function names in the sidebar is the reason I still use Coda. Our workplace code base is so sprawled, this feature alone saves me so much grief.

<comment><USER31> Have you tried this? SHows functions in a tag bar in vim.

<http://www.vim.org/scripts/script.php?script_id=273>

<comment><USER30> I think I tried that one out when I was giving Vim a whirl. Unfortunately I couldn't get into it. If there was something similar for Sublime Text 2, I would be very interested.

<comment><USER32> Command/Ctrl+R will bring up the symbol explorer in ST2. Basically the same as Coda's function explorer.

I do wish it could be a permanent fixture on the sidebar though... not sure if this is possible or not with a plugin.

</comment></comment></comment></comment></comment><comment><USER33> I really did enjoy using Coda when I was doing PHP work around 2008-2009 (got my company to buy me a copy). Now that I work primarily in Ruby and forced myself to learn Vim a few months ago, I can't ever imagine myself going back to Coda.

That said, it looks like they added a bunch of features I would have loved back then.

</comment><comment><USER34> Is there an upgrade path for Coda 1 users? Also while the video is presented well, I think they need to change the music - Its far too distracting..

<comment><USER25> Direct customers (e.g. not the Mac App Store) can upgrade for $75. Recent purchasers (via the direct channel and after April 10, 2012) can get it for free. In addition, every one can get it for $50 (half-off) for the first 24 hours, which is a great tactic if you want to elicit impulse buys through a channel that doesn't support refunds—I'm looking at you Mac App Store.

</comment></comment><comment><USER35> Users really had to wait so they could build a MySQL editor? Who was asking for that? I'm pretty disappointed, unlike the voiceover for that video. Think I'll stick to Espresso.

</comment><comment><USER36> Having used Coda since 1.0 as well I have to say I'm very disappointed with this release. The GUI looks like crap and is not intuitive at all.

All the file navigation can easily be done with a keyboard short cut similar to sublime, no need for 50 different ways to do it. The mysql editor looks half assed as well. Where is the improved support for Ruby they mentioned?

Coda 2 looks like an improved version of iweb in the ilife suite.

Really expected more for Panic as I was really excited for Coda 2.

</comment><comment><USER37> Looks nice, I'm still trialling Sublime text 2 so theres a chance for Panic to win me back - although I am loving Sublime, Coda is what I learnt with so ...

I wonder if they will honour the offer they made during a coda 1 promotion in early 2009. I forget the exact details but there was the promise of a code 2 discount or some kind.

Either way, nice job

<comment><USER38> They mentioned in the blog post about the release that it would be 50% for the first 24 hours, and a free upgrade for recent purchasers.

<comment><USER37> Fair play, didn't read the blog post. Just watched the video

</comment></comment></comment><comment><USER39> It is not clear to me what Coda is. They certainly do not mention it at the site. It looks like some form of IDE but there no other information. I am not going to go through the tutorials without some simple explanation of what it is and where it is applicable.

<comment><USER40> Are you serious? The first paragraph:

"You code the web. We revolutionized that process in Coda, putting everything in one place. An editor. Terminal. CSS. Files."

<comment><USER39> What languages does it support? What OS? or is it a Web App itself?

<comment><USER41> The Mac App Store icon infers that it's a Mac app. As for languages, you're right that it isn't clear. Having said that, the main window is a text editor which performs highlighting on all of the major web languages (in Coda 1.x anyway).

<comment><USER42> If you're not a Mac user, how would you know what the App Store icon looks like?

There was nothing in the Help/FAQ either, so it wasn't until I manually navigated to panic.com, seeing that they do Apple apps, that I finally got pretty sure it wouldn't be available for my platform.

<comment> dorian-graph There comes a point where preparing for all levels of pedantry isn't wise and it's fine for people to assume a certain level of knowledge/experience from their target audience especially if their target audience isn't everyone.

</comment></comment></comment></comment></comment></comment><comment><USER43> * AirPreview requires separate purchase of Diet Coda.*

Thats a pretty big bummer considering it's the most compelling feature. Also, I know panic is a mac only shop, but platform locked desktop apps seem a bit unsavory these days. Especially applications for developers.

</comment><comment><USER44> Reminds me of Dreamweaver

</comment><comment><USER45> Ack, that music makes me feel like I just found a dark and dangerous bonus level in Mario.

</comment><comment><USER46> Ultimately it's about what you do with the tool, there's not one size fits all editor as far as I know. You don't need to be a CMS themer or Dreamweaver fan to like this, it has all sorts of features that you may or not use if you don't like. What you can do with it it's up to you. For example, I do music and use software that costs around $500 dlls. I know several musicians that are using far less expensive software, with less capabilities and they're making amazing songs. Well?

</comment><comment><USER47> Well, it's about time. I mean, it only took 3 years.

Coda has always been for the "front end" developer. I've moved on to PHPStorm and Sublime. But I will be taking look at Coda 2.

I don't see the cost anywhere?

<comment><USER48> I think it said $50 for the first 24 hours, after that it's a $75 upgrade, $99 new.

</comment></comment><comment><USER49> As someone who really uses vim all the time, this is impressive, even if I am not target user. Coda for me was app that was defining mac as a platform.

</comment><comment><USER50> I want to know more about why they chose to share absolutely nothing in the build-up, launch a gorgeous video today, and then aren't ready to take purchases for 48 more hours?

That just seems like a huge mistake to me. Surely the point of being silent in development was to have this big unveiling. Shouldn't the sale then kick off right now while we're still (in theory) amazed at it?

(Especially with MAS not offering refunds...)

</comment><comment><USER51> Is anyone else unimpressed by what is new given the amount of time they've taken between releases 1 and 2? Coda 1 came out over 5 years ago, and few, if any, of the highlighted new features are new to the world of development, just new to Coda.

I will say I like the embedded editors for colors in CSS, but that was the biggest improvement I think I see.

<comment><USER52> You didn't read anything on the page, did you?

</comment></comment><comment><USER53> I didn't find anything about 'App Sandbox' in the app features/descriptions... Is it fully sandboxed? Because, you know, Apple will enforce sandbox effective June 1st! It means that Apple will pull Coda 2 in about 7 days after its lunch.

I wouldn't buy Coda 2 from the App Store before June 1st if I were you.

<comment><USER54> > It means that Apple will pull Coda 2 in about 7 days after its lunch.

Citation required. Can you back up that statement? Everything else that I've seen indicates that Apple will require apps _submitted_ after June 1 to be sandboxed. I've seen nothing indicating they'll pull old apps.

Furthermore, what's to say they can't get custom entitlements? Apple is extremely eager to have every app sandboxed and has emphasized many times they'll work with apps who need permissions not in the standard set of entitlements to build custom entitlements.

<comment><USER53> I wouldn't give Panic $49, $79 or $99 (or even $0.99) _just_ for Coda 18.104.22.168. I want all the future updates, which, if Apple does not grant custom entitlements, wouldn't make it into the App Store.

I have a huge respect for Panic (specially for their taste in design) and I use their products, but not addressing this issue seems very unprofessional to me.

</comment></comment></comment><comment><USER55> Coda works really well for WordPress work and for static sites. I'm interested to see if the new version is strong for uses beyond that.

I am very excited for Diet Coda. I can't see myself doing serious code work on an iPad, but for quick fixes and small work, it would be great to have it on the go.

</comment><comment><USER56> Finally!!! Coda's editor really shines with their sidebar IMO. Being able to drag and drop files, seeing meaningful icons, built in ftp editor when you need it... etc. I just hope it has a split-pane feature the way sublime does as I have become addicted to the way that works.

</comment><comment><USER57> I own a coda 1 license, but i'm not sure any of this will pull me away from sublime text 2.

I only use coda for remote wordpress sites. It looks like it's even better for that, but for anything significant, sublime, along with a raft of individual tools seems to work way better.

</comment><comment><USER58> I'll probably pass on this one. I used Coda 1 for a bit but then moved onto TextMate when I started doing almost everything with Rails.

The one Panic app I still use often is Transmit, so I wouldn't mind if they worked on upgrading that now that Coda 2 is near completion.

</comment><comment><USER59> I use coda for my personal site and a non-profit site I work on on the side. Its not as hard core as my work setup, but its fast and easy and I do like it. Its easy and fast but was getting a little long in the tooth.

I'm all optimism about this.

</comment><comment><USER60> Say what you want, but that demo was absolutely brilliant.

I am not the target audience, though.

</comment><comment><USER61> It looks awesome, but I don't think I would enjoy this fancy GUI after a couple of weeks using it. It looks like a replacement for dreamweaver or iWeb.

</comment><comment><USER62> "Proverbial butter." Nice. Most of the features I hop over to Espresso for (code folding, for one) are in Coda 2, yay!

</comment><comment><USER63> They added Git support but not Mercurial :(

</comment><comment><USER64> Until I can set filters on the file display so I don't see .pyc files I'll be giving Coda a pass.

</comment><comment><USER65> via @panic:

Tap the \ (backslash) key while the video is playing to reveal the entire screen.

<comment><USER66> Is it just me that thinks this is rather stupid? Now they are downloading much more data then needed and pre rendering the camera movement should also get a better frame rate and the edges would have been anti-aliased.

</comment></comment><comment><USER67> Is there any reason to use this over something from JetBrains?

</comment><comment><USER68> I'll purchase if it supports Wordpress in a meaningful way.

<comment><USER69> There's a third-party syntax mode for WordPress on Coda 1, I suspect it will still work for v2: [http://wordpress.org/support/topic/wordpress-syntax-mode- for...](http://wordpress.org/support/topic/wordpress-syntax-mode-for-coda- editor)

</comment></comment><comment><USER70> Does anyone know wether it will be good for python dev?

<comment><USER71> I'd be surprised. Coda 1 can edit lots of file types, but it's clearly intended for a PHP workflow: edit files, preview them, upload to the server. Not sure the whizzy features are going to help you much.

</comment></comment><comment><USER72> is it useful for anything other than php/css/html?

<comment><USER20> At least with Coda 1, Ruby and Python are supported too -- and JavaScript, obv. But it's not as robust as some more hardcore text editors.

</comment></comment><comment><USER73> Does a license to Coda 1 include a free upgrade?

<comment><USER40> Nope, but it does give you $20 off. $79 vs $99. Also, the app is $50 for everyone for the first 24 hours.

A bit of a bitter pill, for sure, but considering that it's a total rewrite with massive new features, it seems fair.

<comment><USER73> "If you bought Coda 1 very recently (after April 10, 2012) directly from us, you are entitled to a free upgrade. Unfortunately, Apple does not provide us a way to give free upgrades to all customers who purchased Coda 1 from the Mac App Store recently"

That's what I was looking for - I bought it in the last month.

Thanks for your response.

</comment></comment></comment><comment><USER74> 1\. Full File Browser

2\. List View and Groups [for Sites]

3\. Git support

These features make me incredibly happy. Though I will probably stick to maintaining my ragtag collection of tools (vim, cli tools etc.)

I'm wondering if there will be an upgrade license.</comment>


Krugman's Baby-Sitting Co-op Explains The Design Flaw At The Heart Of Bitcoin - <AUTHOR> http://www.forbes.com/sites/pascalemmanuelgobry/2013/04/05/krugman-baby-sitting-co-op-bitcoin/

<comment><USER2> This example always amuses me because Krugman guilelessly puts forth the case for central control while glossing over the results:

>> _"But eventually the economists prevailed. More coupons were issued, couples became more willing to go out, opportunities to baby-sit multiplied, and everyone was happy. Eventually, of course, the co-op issued too much scrip, leading to different problems ..."_ <<

Of course, these different problems are just ignored. Krugman never seems to want to discuss whether these new problems, entirely caused by centralized control, are worse than the problem the "alert management" intended to solve in the first place.

It's what makes his oft-use example so excellent. Here you had, presumably, a small group of highly-educated and, presumably, reasonably intelligent folks who _couldn't even manage an economy with 150 homogenous players_. And yet, we expect much better results when we introduce billions of players and millions of additional variables.

<comment><USER3> i think its ironic that you're putting forth the case for unmanaged economies while glossing over the results.

i think most economists (including Krugman) would agree that managing an economy is hard, and that oftentimes, the people in charge don't get it right. but that doesn't mean the alternative is better.

in this specific case (bitcoin), the alternative to managing the money supply centrally is a fixed supply of money. in an environment where the economy (the gross output of the market) is growing, that leads to deflation. krugman points out that deflation slows down economic activity, possibly catastrophically. do you disagree?

</comment></comment><comment><USER4> To me it seems the problem with the Babysitting coop was price fixing. The price of of an hour of babysitting was always 1. If the price of an hour of babysitting was allowed to float you would not have the shortages.

<comment><USER5> Float compared to what? The price of an hour of babysitting was always 1 because the only thing on the exchange is an hour of babysitting.

I suppose you could argue some hours of babysitting are more valuable than others, and people could negotiate, say, 4 hours for 5 coupons or vice versa. It's not clear this either (a) _wasn't_ already done on some ad hoc basis (I'd imagine if it was agreeable to both parties, it'd probably happen) or (b) would have provided a solution to the liquidity problem, though.

<comment><USER6> Float compared to supply and demand in a free market. Instead of issuing 1-hour coupons, they should have issued an arbitrary currency, say, Shillings. Then buyers can request babysitting paying at 1 shilling per hour, and sellers could say that they want 1.3 shillings per hour. The value of the currency needs to float with supply and demand.

The whole argument in the article is a pathetic straw-man. The value of bitcoin floats with supply and demand. When the supply is fixed when bitcoins can no longer be mined, then the supply is based on how much is circulating vs being held.

<comment><USER7> The value of bitcoins floats with supply and demand, that is correct. However the demand for any currency is tied to the supply/demand for the total number of goods that are sold/bought with that currency. As the value of these goods rises over time towards infinity demand for bitcoins will rise over time towards infinity. Supply of bitcoins on the other hand is inevitably slowing down and thereby the value of bitcoins will rise towards infinity.

This makes it very cheap to "import" goods but prohibitively expensive to "export" any. It also provides a huge incentive not to spend or lend any money. Demand will fall, loans will be harder to get, innovation will come to a standstill and overall the economy will collapse.

This is called deflation and this is why we have huge central banks full of well educated people carefully monitoring the economy to adjust inflation and deflation.

<comment><USER6> Interesting. Do we have the same situation with gold? Continuous deflation, caused by constant supply combined with increasing demand, causing its value to rise to infinity?

How is gold different?

<comment><USER7> Indeed it does apply to gold and to currencies using the [Gold Standard](<http://en.wikipedia.org/wiki/Gold_standard>) which has caused problems in the past, which is why it isn't used anymore as a currency on any significant scale.

</comment></comment></comment></comment></comment></comment><comment><USER8> _"Now, it's worth noting that this fatal flaw of Bitcoin is not a fatal flaw for all cryptocurrencies or algorithmic currencies. One can imagine a Bitcoin- like currency with a smart algorithmic central bank (indeed, Bitcoin does have an algorithmic central bank–just an economically illiterate one)."_

It's also worth noting that it's theoretically possible for Bitcoin's "monetary philosophy" to change over time.

If a majority of Bitcoin miners, and thus (in theory) the "economic majority" (<https://en.bitcoin.it/wiki/Economic_majority>), agree on changes to the system (for example, the rate of mining) everyone can migrate to newer versions of the software that will accept those rules, and those who don't will risk their version of the blockchain not being accepted by the majority of users.

One interesting question is what happens if there's a fairly even split between the group that accepts the old and new rules. Would the value of each blockchain be effectively halved?

<comment><USER9> Realistically, Bitcoiners can't even agree to fix unspendable UTXOs. I can't imagine that they would ever agree to devalue their own holdings.

<comment><USER10> What is there to fix? Can't a minority client just blackball UTXOs, allowing them to exist in the blockchain but refusing to publish or accept transactions built off them?

By definition, a UTXO is not in the history of good money.

<comment><USER9> That's a good point. Someone could troll you by spending such an output in a "valid" transaction which you would treat as invalid, but who cares.

</comment></comment></comment></comment><comment><USER11> The overwhelming main gripe I read not only on HN, but also on business websites is that Bitcoins aren't US dollars.

It reminds me of the apocryphal, famous Ford quote, "If I had asked my customers what they wanted they would have said a faster horse."

</comment><comment><USER12> Can someone pro-bitcoin provide a counterpoint to the deflationary spiral criticism? I don't have enough of an understanding in economics to think of one.

<comment><USER13> The flaw in the argument is that BitCoin is not (currently) a unit of account (we don't price contracts or goods or services in BTC), and is (nearly) infinitely divisible.

So even if 90% (or 99%) of all BTC is being hoarded, the other 10% (or 1%) can be divided up for use in transactions. That much speculations will cause wild gyrations in value and massive short term volatility, but the people using BTC to transact JUST DON'T CARE.

I really don't care if I'm buying my $1000 flat screen with 1 BTC or 0.0001 BTC. Neither does the merchant. I bought the BTC, sent it to the merchant, and the merchant sold it so quickly that the value didn't change much, and we are happy.

So that's the short term. In the long run, the volatility might decrease as the total market capitalization increases to 10x or 1000x of its current value.

Then we can start to think about using it as a unit of account. If we do, we may enter a deflationary spiral, but by then BTC will already be used in an enormous swath of the economy.

So I interpret Krugman's argument not so much that BTC CAN'T take over the world, but that it SHOULDN'T take over the world. (I'm not sure if I agree. Many economists have been arguing over this point for decades, and I'm not smart enough to sort it all out.)

<comment><USER14> That is not a flaw in the argument - that is a flaw in your understanding of the argument, which makes you think this is a valid rebuttal.

Money is supposed to _represent_ value. Not to actually _be_ value. There are new humans arriving in the world all the time. And new resources are being mined from the earth, and created intellectually all the time.

If the money supply does not match these new things then the currency fails.

You can't just do a "currency split" and issue more notes - doing that effectively tells everyone their resources are half as valuable which is clearly wrong - the value of the resources didn't change.

You need to issue more currency so that the sum total of money available is equal to the sum total of value in the world. Any currency that doesn't do that fails.

<comment><USER15> > You need to issue more currency so that the sum total of money available is > equal to the sum total of value in the world. Any currency that doesn't do > that fails.

That's only if you want the currency to maintain a stable value, neither inflationary nor deflationary.

Alternatively, the currency will have deflation. It's not obvious that that necessarily implies "failing".

<comment><USER16> No one will be able to use it for transactions because everyone will hoard it- buying the currency will be impossible.

</comment></comment></comment></comment></comment><comment><USER17> Well, I just linked to the cited Krugman article. In case anyone else has difficulty with the pkarchive.org link, here's another source: [http://www.slate.com/articles/business/the_dismal_science/19...](http://www.slate.com/articles/business/the_dismal_science/1998/08/babysitting_the_economy.html)

</comment><comment><USER18> In other words, when people run out of physical goods to trade, they will start trading IOUs, at which point inflation has occurred within your economy whether you intended it to or not.

<comment><USER19> Is it "inflation" if each new IOU is accompanied by a corresponding unit of production?

I thought not, but I am no expert.

<comment><USER18> Yes, because an IOU can be traded after its initial creation, and due to peoples inherent desire to save (hoard) assets theres no guarantee the IOU will ever be cashed in. Inflation occurs because people learn that more IOUs can be issued then are ever cashed in.

Economies are naturally structured around this asynchronous trading structure because we want to help each other survive.

</comment></comment></comment><comment><USER20> In 1998, Krugman also predicted that "by 2005 or so, it will become clear that the Internet's impact on the economy has been no greater than the fax machine's."

[http://web.archive.org/web/19980610100009/www.redherring.com...](http://web.archive.org/web/19980610100009/www.redherring.com/mag/issue55/economics.html)

<comment><USER21> That has nothing to do with whether he is right or wrong about this issue, though.

</comment></comment><comment><USER22> The mistake in the article is that bitcoins can subdivide AND increase in value. Bitcoins are not going to have liquidity crisis, as much as some people seem to want it to.

<comment><USER23> If/when bitcoins ever become an important currency they will have all the same problems as other currencies, and others unique to being bitcoins. E.g. central banks will try to manipulate them, governments will tax and regulate them, and people will speculate on them.

Being able to subdivide and increase in value are not attributes unique to bitcoins.

Oh, and the article DOES address this exact point.

<comment><USER22> > Being able to subdivide and increase in value are not attributes unique to > bitcoins.

I didn't claim that.

> Oh, and the article DOES address this exact point.

No, they always assume the value of a coin remains constant when discussing subdivision.

<comment><USER23> > There are some objections to this: for example, that since each bitcoin can > be infinitely divided into components, the money supply can keep growing. > But that's not related. If you have a $10 bill and I replace it with ten $1 > bills, do you feel richer?

This seems to address the point to me. If the supply of dollars is constrained (liquidity trap) then deflation does NOT make people happier.

<comment><USER22> If I have ten $1 bills and they are each worth $10 of previous spending power, I would ABSOLUTELY feel richer.

</comment></comment></comment></comment></comment><comment><USER24> A slightly related article I read recently about how should we evaluate the claims of people much smarter than ourselves. i.e. in this specific article the example is if Krugman makes some claim about economics should we just accept them as he is probably leagues ahead in terms of knowledge and expierience in the subject.

[http://theumlaut.com/2013/03/13/paul-krugman-is-brilliant- bu...](http://theumlaut.com/2013/03/13/paul-krugman-is-brilliant-but-is-he- meta-rational/)

</comment><comment><USER25> "If you have a $10 bill and I replace it with ten $1 bills, do you feel richer?"

Yes, If I split my 10 into 10 ones and if 9 can pay today for something that cost 10 yesterday, I feel richer.

This causes folks to save and horde like in Japan. Because its deflationary.

It's more difficult to control the masses via monetary policy if things are deflationary... That's why governments try to maintain slight inflation. Comfortable folks don't produce for the government.

<comment><USER19> It has nothing to do with "comfortable folks producing for the government" and everything to do with coordinating production and consumption. If everyone produces for 20 years and accumulates money, and there is no inflation for 20 years, and then they all try to retire and spend it, but there is no one to produce, since everyone wants to retire, you get hyperinflation chasing the small amount of available goods. Alternatively you inflate the currency for 20 years, to encourage people to consume their savings as a sustainable pace.

Remember: if you spend your inflationary money NOW on durable goods (canned food, wood, whatever), then you can trade those goods for inflated currency later, and not lose any value.

But, if you don't spend your money (maybe because there is nothing on the market worth buying), then inflation is the natural correction to bring the money supply into balance with the goods supply.

</comment></comment><comment><USER26> I don't quite buy the analogy. Seems to me that part of the problem was having tokens that could only be exchanged for one thing, and even then at a fixed exchange rate.

<comment><USER27> Here the problem is that bitcoins are illiquid: you can't spend them freely on most goods and services, and you can't get a consistent exchange rate into a liquid currency, and the supply problem means that hoarding is sensible... right up until the crash.

</comment></comment><comment><USER28> Another article that gets it wrong. _sigh_

 _"I've also been told that this is only valid if the entire world is on Bitcoin"_

So far the author is right. The whole world does not run on Bitcoin only, therefore the arguments against Bitcoin do not apply. But here is where he gets it wrong:

 _"but if you think about the world today, that's not true. There are plenty of currencies out there, and the supply of some of them is too low, and that hurts the people who use that currency. The fact that the dollar exists doesn't prevent the yen from being too strong."_

The author does not cite examples of people hurt by a currency when a supply is low, because he is wrong: there are no such examples.

I don't know why he cites the Yen. The Japanese economy is not that bad. It is not that great either. But it is doing okay. Therefore if Japan is okay with a deflationary currency, why would not Bitcoin be okay too?

Or someone may cite the example of the failure of the gold standard in the US in the 1960s, but it would be incorrect. The gold standard failed because the US Federal Reserve continued to increase notes in circulation, while not replenishing gold reserves, which triggered all sorts of bad consequences, see [1]. By contrast, in Bitcoin it is algorithmically _impossible_ to increase "notes" (coins) in circulation beyond the limit of 21M coins.

[1] See <http://mises.org/daily/3325>

</comment><comment><USER29> Watch out. You posted an article on HN that doesn't praise Bitcoin. And, you know, all software developers are also economists. Expect a backlash.

</comment><comment><USER30> One thing that strikes me is the person with the most coupons happens to be the person with the least amount of need for the coupons. Therefore they will never redeem them and eventually everyone runs out.

A true currency (and Bitcoin if its a true currency) allows the most avid babysitter to get other things with it instead of what she already has a surplus of.

</comment><comment><USER31> His argument seems to say that the LIQUID supply of bitcoins is shrinking because people are hoarding them. You can make the same argument for stocks or anything else that is traded for cash, but it's wrong. Everybody will have a price that they're willing to sell at - it's the fundamental idea underlying every exchange market.

</comment><comment><USER32> Why is Krugman being thought of as a genius in predicting market trends and pricing assets? He has never proven himself in this way, he does not manage money, he is only rich from book sales. Krugman is just a politician who promotes his own opinion of how the US economy should be handled.

</comment><comment><USER30> Coupons are not currency. They were trading coupons of 1 hour babysitting to save from spending real currency on hours of babysitting.

<comment><USER14> Of course a coupon is a currency. What do you thing a currency is? It's a store of value.

<comment><USER30> Just because something has value does not make it a currency. If that coupon ONLY gets you a reduction in price off something then its a discount. Here is another tidbit that makes it not a currency: coupons are intended to not be redeemed more than once.

If only one person can ever use it then it fails at its intention of goods exchange. It's not currency.

</comment></comment></comment><comment><USER33> The key point is that bitcoin is not actually a currency (like the dollar or euro), it is a commodity (like gold or silver). Thus it will be subject to speculative bubbles and unpredictable swings in value, and the typical holder will not be able to do much about that.

Central banks and fiat currency remove the danger of speculative bubbles...or at least, they centralize the danger to a single, publicly controlled entity.

<comment><USER22> > they centralize the danger to a single, publicly controlled entity.

Come to think of it, we should centralize the backbone for the internet in the white house basement, so that we "centralize the danger to a single, publicly controlled entity."

<comment><USER33> The core address data of the Internet is in fact centralized on behalf of the U.S. government by ICANN.

<comment><USER22> Fair point.

</comment></comment></comment></comment><comment><USER34> Bitcoin can't be debased.

a. That's a bug

b. That's a feature

They certainly were designed to be that way, and that was intended to be in sharp contrast with the conventional way currency is managed.

A more sophisticated argument about bitcoin might go this way:

a. Bitcoin provides an alternative that is both a useful experiment and is edifying in a way that may help keep the managers of currency systems honest.

b. Bitcoin is like releasing an uncontrolled nanotech experiment into the environment that could turn all our money into grey goo, and governments better put in place measures to prevent and eradicate experiments like this.</comment>


Dissent: accountable anonymous group communication - <AUTHOR> http://dedis.cs.yale.edu/2010/anon/ <comment><USER2> There are something like 20-ish papers here. I have skimmed several of them without any clear answer to this question:

How exactly do you stop sockpuppetry while maintaining anonymity?

In order to ensure that a person cannot create more than 1 account, it would be necessary to observe some property of the person that is difficult to alter (such as their appearance, or their social security number) for uniqueness on the network.

Now if this network is truly anonymous, then it must be disjoint from every other network. And there is at least one other network ("real life"), so whatever this property is, must be something that an adversary in the real- life network would not be able to compare to the anonymous network.

And so certainly, it must not be some property that a person in the real-life network could observe by following you around or ruffling through your drawers and then compare to the answer you gave to sign up for the anonymous network. So it must be something in your head (like a password).

But if it is in your head, isn't it easily changed, and this property would be exploitable to create sockpuppets?

I must have missed something fundamental here, possibly in terminology. Can somebody who is current on the research here enlighten me?

<comment><USER3> The way this is usually handled is anonymous credentials. You force someone to identify themselves uniquely (full name, passport, SSN, DNA, photo, etc). You then issue them a credential that is anonymous (i.e. when shown, you can't link it with when it was issued or previously shown). Furthermore, you set up these credentials so that if they are used too many times (i.e. cloned) then the identity is revealed.

You then require them to show the untraceable credential each time they submit a message.

<comment><USER4> So the way this maintains anonymity is by not trying?

What you've described is a central authority architecture which is in charge of issuing the credentials. But we already have CA authorities that issue SSL certs. They're brittle to government influence, because it's impossible to know whether the government has acquired the secret keys. In your case it'd be impossible to know whether the hypothetical CA has stored your secret credential / whether they've told anyone your real identity.

Even if this model were to work, it wouldn't protect users from themselves. Here's a fascinating read about the problems of staying anonymous even in an environment with perfect anonymity guarantees: [https://whonix.org/wiki/DoNot](https://whonix.org/wiki/DoNot)

For example, no anonymity network can protect against stylometry, so that's always a concern. I was also shocked to realize that something as simple as automated time synchronization will reveal your general location when using Tor, because your machine requests a time update for your specific timezone. You have to set your clock to UTC to avoid that. There are about two dozen other vectors by which you can accidentally reveal your true identity even when using a rock-solid protocol. Anyone who's interested in this should read the entirety of the Whonix wiki. In addition to being comprehensive, it's also a lot of fun to read.

(Most of my comment was meandering and not really related to yours. It's just interesting how difficult perfect anonymity is. It's probably true to say that getting the tech implemented correctly is only a small fraction of the total amount of work required to be truly anonymous.)

<comment><USER3> I should clarify. The credentials are anonymous even given a malicious CA. This is a cryptographic guarantee assuming the Strong RSA assumption holds.

The only thing the CA can do is produce a list of people they issued credentials too.

</comment></comment></comment></comment><comment><USER5> Apologies in advance for the wall of text, but the first half is basically just a summary of their protocol for people who don't want to try to identify where the actual information resides (it appears to be [http://dedis.cs.yale.edu/2010/anon/pres/120104-dissent.pdf](http://dedis.cs.yale.edu/2010/anon/pres/120104-dissent.pdf)).

As I understand it, the basic idea is that there is a network made up of N clients and M servers, with the clients (and potentially servers) identifiable in some external fashion (IP addresses or GPG keys or whatever, it's unimportant to the protocol) and we want to make it possible for any of the clients to broadcast a message without anyone being able to tell which client it came from.

So what happens is each client and each server generate a Diffie-Hellman key which is associated with their actual external identity. Then each client establishes a unique secret with each server (and vice versa, naturally). These unique secrets are used to produce N times M unique bitstreams using PRNGs (so each client has a bitstream corresponding to every server that exists, and each server has a bitstream corresponding to each client that exists).

Then each client XORs together the bitstreams from the unique secret it shares with each server, and each server does the same thing for each client's shared secret. Now there are N + M bitstreams, with the nice property that if you XOR together all of them they all cancel out (because every client-server pairing occurs in the bitstream from that client and the bitstream from that server).

Furthermore, if one client also XORs some data into the bitstream that they publish, no one else can tell, it still contains a bunch of indistinguishable- from-noise data to everyone else who might look. But then when we XOR together all N + M bitstreams, we end up with everything cancelling out except for that extra data that one client added.

So then the Dissent protocol pulls in another construct, and uses something called MIX to shuffle a set of public keys generated by the peers, and uses these public keys to establish a transmission order, essentially reimplementing TDMA (Time-Domain Multiple Access) in a digital domain with signatures.

In my opinion as a hobbyist interested in this stuff, the whole "everyone produces a bitstream and they magically evaporate leaving behind only the data everyone transmitted" thing is almost magically cool. The time-domain multiplexing is less cool, and my EE background compels me to wonder if a meaningful analogue to CDMA or OFDM could be developed. Well, obviously they could be _developed_ the real question is "could they be useful?".

It's also sort of interesting how the fact that we can't ever be allowed to know when a given peer is transmitting means that the design becomes more "continuous", with data being transmitted by everyone at all times so that the real transmissions can be disguised. I wonder if the theoretical perfectness could be loosened somewhat to allow only, say, 10% of peers to have to be transmitting at any given time (in the long run this could make it possible to identify a transmitter uniquely, but not so quickly that it wouldn't be useful still).

Unfortunately, the second bullet-point (accountability) goes close to unfulfilled. And I feel like it sort of has to, since any method which could determine where malicious data comes from can also be used to undermine the anonymity of the system for everyone else. There's a _kind_ of accountability, which is that the peers themselves can be associated with a public identity without anyone being able to tell which peer produced a given message, even in theory, but it doesn't extend to any system with open registration, because it doesn't handle the "sock puppet" problem at all.

But personally I think the sock puppet problem is pretty much un-silver- bullet-able. The best we can probably ever hope to do for "general purpose" uses is probably a combination of a cryptographic proof-of-work algorithm, public-key signatures to _allow_ (though not force) persistent identity, and some sort of reputation system.

<comment><USER5> I've been thinking more about the whole "better multiplexing" issue for a bit now, and I suspect that some sort of [http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_w...](http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_with_collision_detection) type of solution is ideal for this use case. Because if you think about it, two transmitters at once is not an unrecoverable failure mode, in fact it's easier to handle here than in, say, the original ethernet standard, because with packet-based internet stuff we can do things like changing the data rate on the fly in response to collisions.

Currently the system I'm imagining works as follows: Every T seconds a new packet is initiated, and fancy spanning tree relaying or whatever is used, and eventually everyone has the XOR of all server and client versions of the packet, which happens to be the XOR of whatever various clients happened to include into their packet. Now the additional information for a client who chooses to add that will be the payload plus a checksum value (which must _not_ be homomorphic under the XOR operation). If one client transmits, the checksum passes, and everyone is happy. If multiple clients transmit, they collide, and the checksum does not pass, and each transmitter knows this and waits a random backoff time (number of packets) before trying again. But in addition, a collision is often a signal that the packet rate is too low, so collisions also cause the packet period T to decrease (and lack of messages will cause it to increase, naturally).

So I think the basic "matrix of shared secrets" construct can be extended to allow low-overhead (for values where "low" means "on the order of 3x") communications, because dynamically varying the period between packets and allowing anyone to try transmitting during any packet time will tend to mean that when no one is transmitting bandwidth drops to a very low level (I could easily believe 16-byte idle packets every 5 seconds for something where absolutely low latency isn't a requirement).

<comment><USER6> Two problems with unscheduled communications: 1\. It allows the adversary to disrupt communications by continuously sending junk. Solving this problem was a major goal of Dissent not adequately handled by previous designs based on Dining Cryptographers networks. 2\. Without a schedule telling everybody when to send _something_ , the first guy to talk is obviously the sender, destroying anonymity.

</comment></comment></comment><comment><USER7> I might just be tired, but I cannot actually come up with a reason this would be useful. Someone help me out?

</comment><comment><USER8> We decided to build an anonymous group communication platform with some other assumptions and requirements:

In our case, speed was an issue. And so was encryption of communication. + We did not want anyone except Bob and Alice to know what they were talking about. We did want to allow formation of groups... ( [https://register.blib.us](https://register.blib.us) )

<comment><USER4> I tried your demo and immediately got a "SSL cert not trusted!" chrome error. [https://rrc.imp.blib.us/link/album/private?albumid=117bc3](https://rrc.imp.blib.us/link/album/private?albumid=117bc3)

<comment><USER8> In our system, every user generates a self-signed certificate and has the option of buying a signed certificate. That demo is from a user of the system that did not buy a signed certificate.

<comment><USER4> As a user, all I see is a website saying they take security seriously and then pointing me at a demo with a broken SSL cert.

I realize that's probably an unfair characterization, but you have to understand that's what every user is going to think. You'll also have to work on your message if you want to get people using this, because it's very hard to understand what exactly your website does. I had to do a double-take because the website says it's a tool for building a personal library of books, not anonymous group discussion.

<comment><USER8> Agreed. Will put a signed certificate for the demo. Thanks for the input.</comment></comment></comment></comment></comment>


New European, U.S. data transfer pact agreed - <AUTHOR> http://www.reuters.com/article/us-eu-dataprotection-usa-accord-idUSKCN0VB1RN <comment><USER2> Not really, it still needs to be ratified by the member states of the EU (and even after that citizens in some of the states can start a referendum about it) and after that it can still be shot down by the European Court. The pact is so vague about the protection of European citizens that there's a good chance that the European Court of Justice won't accept it, as they haven't fixed all of the problems that were in the previous "safe haven" pact.

<comment><USER3> >Not really, it still needs to be ratified by the member states of the EU (and even after that citizens in some of the states can start a referendum about it)

That's not true.

Under the Data Protection Directive the Commission, acting alone, can do this.

Article 25(6):

"The Commission may find, in accordance with the procedure referred to in Article 31 (2), that a third country ensures an adequate level of protection within the meaning of paragraph 2 of this Article, by reason of its domestic law or of the international commitments it has entered into, particularly upon conclusion of the negotiations referred to in paragraph 5, for the protection of the private lives and basic freedoms and rights of individuals.

Member States shall take the measures necessary to comply with the Commission's decision."

>The pact is so vague about the protection of European citizens that there's a good chance that the European Court of Justice won't accept it

I'd go as far as saying it's almost certain.

<comment><USER4> AFAIU the commission can indeed do it and sadly until now it can be considered the most powerful institution in EU. At the same time the commission is not a very democratic institution, because the members and the director of the commission are not elected by the European population and the acts of the commission are not underlying to much control from other institutions.

If I understood it, the situation got a bit better last years as the parliament has a bit more power now - but I don't know the mechanics.

Disclaimer: This is only my uninformed understanding as an EU citizen.

<comment><USER5> The Commission needs to be voted in by the European Parliament. They can't propose a Commission on their own (only the Council can do so which consists of the head of states or governments). However, the parliament can vote against the proposal and forced candidates out in the past.

It's actually not too different from how governments are elected in many countries.

</comment></comment></comment></comment><comment> k-mcgrady Maybe I'm not understanding this right but it seems like the EU has decided to trust US government agencies to provide adequate oversight/policing of European's data usage in the US with only very minimal EU involvement. Impossible for us to know exactly but that's how it comes across to me in the article. Seems like it would make more sense for the EU to police this exclusively or to have their own ombudsman rather than relying on the US one to be impartial.

<comment><USER6> American companies don't do that for US citizens, or pretend to comply but don't do so really. Seriously, Americans don't trust their own government or any corporation with with any data. And they have very good reasons to do so, because those corporations and the US government will use that data for anything whatsoever that they feel is protecting whatever laws they have come up with and instituted. Whether that's for actual criminal activities, protecting intellectual property, or even protecting American corporate or economic interests. American corporations will use that data to sell people more stuff and build as detailed of a profile on them as possible. How a third party does so is beyond insanity to me. It's not reasonable at all. Period.

<comment><USER7> > Americans don't trust their own government or any corporation with with any > data

wat?

Americans give so much data to companies.

<comment><USER8> I believe the implication is, "Americans don't trust their own government or any corporation to abide by their publicly stated policies on how and when data is collected and used."

</comment></comment></comment></comment><comment><USER9> > Strong obligations on companies handling Europeans' personal data and robust > enforcement: U.S. companies wishing to import personal data from Europe will > need to commit to robust obligations on how personal data is processed and > individual rights are guaranteed. The Department of Commerce will monitor > that companies publish their commitments, which makes them enforceable under > U.S. law by the US. Federal Trade Commission.

[http://europa.eu/rapid/press- release_IP-16-216_en.htm](http://europa.eu/rapid/press- release_IP-16-216_en.htm)

This one reads like a big fat _nothing_. So it's the FTC who will be monitoring if the US companies treat EU citizens' privacy well? Yeah, what could possibly go wrong? It's not like the FTC hasn't already been virtually impotent in punishing privacy violations from US with small fines and "20 year privacy monitoring", which is about the same as credit rating agencies giving big banks AAA ratings in 2008.

EDIT: Oh wait, it's actually the Department of Commerce - only the most corporate-friendly agency in the U.S - the one that will be doing the monitoring. Lovely.

</comment><comment><USER10> So it looks like this needs (from EU perspective) another round of lawsuits to get this overthrown again - since the oversight by the US DoC is laughable.

<comment><USER11> Basically the problem with Safe Harbor is Section 702 of the Foreign Intelligence Surveillance Act and Executive Order 12333. The cumulative effect is that all people non US persons are legitimate targets of mass surveillance under US law.

The fix for Safe Harbor was negotiated with Department of Commerce who has no authority to talk about reforming this policy.

Options were

1\. Immediately end the ability of US based digital companies to do business in Europe

2\. Cave completely and have a few months of normalcy before Europe Commission kills the deal.

<comment><USER12> You have a significant misunderstanding of the mechanics of this treaty, FISA, and EO12333.

This treaty: it must be ratified by Congress in order for it to be considered accepted by the EC. Under the U.S. Constitution, this means it would carry the full force of the law. The Commerce Department wouldn't bear the weight of enforcement.

FISA §702: limits collection to targeted non-U.S. persons of foreign intelligence interest at borders (Upstream) and submission of NSLs to U.S. organizations for data on non-U.S. persons. The Privacy Shield agreement only prohibits mass surveillance.

EO12333 does not apply since that collection occurs outside of the United States, and would not be in the jurisdiction of this agreement.

> Department of Commerce who has no authority to talk about reforming this > policy.

No, this agreement was made at the behest of the Senate Committee on Commerce, Science, and Transportation [1]. Since this will be ratified by the Senate, it will carry the full weight of the law.

[1] [http://www.commerce.senate.gov/public/index.cfm/pressrelease...](http://www.commerce.senate.gov/public/index.cfm/pressreleases?ID=91D1C61B-F5C7-44C4-A8A4-801D2973072E)

</comment></comment></comment><comment><USER13> So the U.S. Department of Commerce is to oversee and control compliance to a directive that would hurt commerce in the U.S.?

Nothing to see here, walk on...

<comment><USER7> A directive that if not followed would result in damage to US business interests.

</comment></comment><comment><USER14> _" prevent European Union regulators from restricting data transfers by companies such as Google and Amazon across the Atlantic."_

The regulators wouldn't restrict data transfer - the existing Directive does. The question is not whether the Data Protection agencies can or not restrict data transfers, but whether the courts consider that this new agreement allows companies to comply with the Directive.

</comment><comment><USER15> Really?

" The word 'password' on a computer screen is magnified with a magnifying glass in this picture illustration taken in Berlin May 21, 2013. "

Because that somehow represents a data transfer pact between the EC and the US? I thought that was meant to be a scare-picture of 'hackers'...?

</comment><comment><USER16> see [https://news.ycombinator.com/item?id=11020324](https://news.ycombinator.com/item?id=11020324)

and the "European Commission may be issuing a round-trip to Luxembourg": [http://europe-v-facebook.org/PS_update.pdf](http://europe-v- facebook.org/PS_update.pdf) by @maxschrems

</comment><comment><USER17> Morbidly curious about how Schrems is going to Schrems this one up.

<comment><USER3> He's already intimated that he could take this to back to court

<comment><USER18> I hope he does.

</comment></comment></comment><comment><USER19> If this isn't ratified, I think a lot of programmers are about to learn why free trade agreements are a good thing.

<comment><USER14> As a programmer, bu also a user, I'm very glad that "free" trade agreements don't override our privacy protection laws.</comment></comment>


Ask HN: How to verify that a user is a robot? - <AUTHOR>

Strange question, but very interesting for me :)
So, you you wanna check, that user is NOT a robot - you can use captcha or something, that robots can't do well.
But, if you need check, that user is a robot?
For example, we create some multiplayer game, were players will programming robots. [this just example, imagine, that we can't run user code on server]. In this case, user can create some UI for a this game and play game by himself. This is not good for a game balance and other game things.
So, we must check, that user is a robot!
We can send request like "calculate MD5 summ of this or that", but programmer can automatize only this part, and continue to play himself with UI.
So,how can we verify this?
ps. sorry for bad english, but i hope, you understand what I mean. <comment><USER2> Make them play 10 games at the same time. (Perhaps in different shards/worlds to avoid cooperation between the different "personalities".)

<comment><AUTHOR> Nice idea. But in this case, i need to verify, that this is the same robot, because robot can do nothing, or play like a noob in first 9 games, but last game will be played by user through UI.

And you can't verify this, because there is different "worlds" and robot can be not so good, for solve some game problem in some random world.

<comment><USER2> One possibility is to drop the best and the worst results, like in a diving contest: [http://en.wikipedia.org/wiki/Diving#Scoring_the_dive](http://en.wikipedia.org/wiki/Diving#Scoring_the_dive)

> _To reduce the subjectivity of scoring in major meets, panels of five or > seven judges are assembled. If five judges then the highest and lowest > scores are discarded and the middle three are summed ..._

Also, make them play 100 games, and drop 10 of them.

This may work if it is a fast paced game. If it is slow paced with a complex strategy, then a good player may play like in a chess simultaneous exhibition [http://en.wikipedia.org/wiki/Simultaneous_exhibition](http://en.wikipedia.org/wiki/Simultaneous_exhibition)</comment></comment></comment>


Ask HN: Why did SpaceX choose to implement touchscreen controls on the Falcon 9? - <AUTHOR> Bob and Doug just mentioned on the stream that they manually controlled the Falcon 9 for a bit - they were using a touchscreen to do that.<p>I always thought that physical 'controllers' are much more reliable and secure - what are the reasons behind using touchscreen to allow for manual navigation of the Falcon 9 rocket? <comment><USER2> I believe that the actual "moving" controllers are physical ones.

In terms of touch screens I'm not a person who has the actual knowledge why, but i can see two main advantages of such solution.

1\. Less parts -> less failures. 2\. It is easier to develop/update the interface, as you don't have to make physical changes to the layout with every iteration.</comment>


James Damore (Google Memo Author) at Joe Rogan Experience - <AUTHOR> https://www.youtube.com/watch?v=uQ1JeII0eGo <comment><USER2> He seems like a reasonable man, not the aggressive misogynist he's been depicted.

<comment><USER3> Subject matter aside, our society will have major problems if we condemn someone before getting a full picture of what they are like.

When a suspected criminal goes on trial, and testifies, and evidence is presented, we are able to decide for ourselves how good or bad a person is.

When someone tells us, "you should hate this person, just trust me", our society turns into an angry mob.

Why?

Whoever people listen to, that person is human, and can make mistakes.

So, if we all rally around a person who is telling us to condemn someone, and we haven't all informed ourselves of the available evidence...

... it is a witch hunt.</comment></comment>


Google image search for black teenagers shows police mugshots - <AUTHOR> https://www.theguardian.com/technology/2016/jun/09/three-black-teenagers-anger-as-google-image-search-shows-police-mugshots <comment><USER2> Just out of curiousity, I did a search for "three white men" and the first two, and several of the first 40 or so results were mugshots as well. After about the first 30-40 there were a lot of mugshots.

</comment><comment><USER3> What is this reflects the reality?</comment>


Landmark computer science proof cascades through physics and math - <AUTHOR> https://www.quantamagazine.org/landmark-computer-science-proof-cascades-through-physics-and-math-20200304/ <comment><USER2> The paper[1] claims that MIP* = RE. At first I wasn't sure whether that was true, because the paper is too long and complicated for me to verify.

But then I found a series of questions and answers written by this quantum guy Scott Aaronson[2] and by this other quantum guy Kenneth Regan[3], who both know a bunch of quantum stuff. Each one of their blog posts makes me more certain about MIP* = RE, to the point that now I'm 99.9% sure it's true, even though I could never verify it myself.

[1] [https://arxiv.org/abs/2001.04383](https://arxiv.org/abs/2001.04383)

[2] [https://www.scottaaronson.com/blog/?p=4512](https://www.scottaaronson.com/blog/?p=4512)

[3] [https://rjlipton.wordpress.com/2020/01/15/halting-is-poly- ti...](https://rjlipton.wordpress.com/2020/01/15/halting-is-poly-time-quantum- provable/)

<comment><USER3> I hadn't heard of Aaronson or Regan before, but perhaps they communicate, and therefore their blog posts might be correlated.

From the new proof though, I'm certain that I can't put an upper or lower bound on the probability of whether they're right.

<comment><USER4> Start with 100 and 0 and go from there

<comment><USER3> What about complex numbers in probabilities?

<comment><USER5> Their modulus squared gives you the probability.

[https://en.wikipedia.org/wiki/Probability_amplitude](https://en.wikipedia.org/wiki/Probability_amplitude)

</comment></comment></comment></comment></comment><comment><USER6> For those interested, the arxiv link: [https://arxiv.org/abs/2001.04383](https://arxiv.org/abs/2001.04383)

Be warned, this is 160 pages of dense math. To anyone complaining that the quanta article is "unclear" or not descriptive enough, there's no way around that when summarizing a dissertation.

<comment><USER7> Some nice and easy afternoon reading

</comment></comment><comment><USER8> From Scott Aaronson: [https://www.scottaaronson.com/blog/?p=4512](https://www.scottaaronson.com/blog/?p=4512)

<comment><USER9> Thanks for the link. Does this mean we're closer to experimentally determining whether infinite-dimensional quantum systems actually exist (rather than being approximated by very large finite ones) ? I vaguely remember this being a topic of discussion when I was in research.

<comment><USER10> "Prior to the new work, mathematicians had wondered whether they could get away with approximating infinite-dimensional matrices by using large finite- dimensional ones instead. Now, because the Connes embedding conjecture is false, they know they can't." Your question is like asking if limits actually exist. It might be answered by first proposing what continuity holds for the quantum system.

<comment><USER9> I'm not sure what you mean by "proposing what continuity holds for the quantum system".

There are a number of results about how measurements of an individual infinite-dimensional quantum system can be approximated to arbitrary degree by an arbitrarily large finite-dimensional system.

This new result seems to suggest that for joint entangled systems there's a "buffer" between measurement results obtained by having arbitrarily many dimensions, and by having infinite dimensions.

I was wondering how practical it could be to actually do an experiment and verify that the buffer line is crossed.

<comment><USER11> The other version of this is to define or find a problem where the difference is smallest. (we know it's not vanishingly small)

</comment></comment></comment></comment></comment><comment><USER12> From what I gathered so far, this is more of a theoretical win for mathematicians, computer scientists, and physicists because it basically proved that if you had two Q-computers with unbounded (read: greater than infinite, basically) power, they could convince a classical computer in poly time that they could run a Q-program to completion correctly, in infinite time.

So basically, we would still need a way to build an unboundedly-powerful pair of Q-computers that were entangled (whoops, forgot that part!) in order to get any direct application for this, then we'd have to actually write the software to run this series of communications the 3 computers exchange from the paper.

So, this is only useful for some unknown, future proof of something else, not to engineer a real-life system with.

<comment><USER13> Hilbert's curve: Is infinite math useful? by 3blue1brown

[https://www.youtube.com/watch?v=3s7h2MHQtxc](https://www.youtube.com/watch?v=3s7h2MHQtxc)

or skip directly to the conclusion;

[https://youtu.be/3s7h2MHQtxc?t=978](https://youtu.be/3s7h2MHQtxc?t=978)

</comment></comment><comment><USER14> A related thread from a few weeks ago: [https://news.ycombinator.com/item?id=22083935](https://news.ycombinator.com/item?id=22083935)

Also these little ones:

[https://news.ycombinator.com/item?id=22079048](https://news.ycombinator.com/item?id=22079048)

[https://news.ycombinator.com/item?id=22077591](https://news.ycombinator.com/item?id=22077591)

I seem to recall others but can't find them. Anyone?

</comment><comment><USER15> TFA starts off a little cheesy, where you might almost think to bounce because the writing is going to just pummel the subject matter beyond recognition.

But then as you continue, you go deeper and deeper through the rabbit hole. Expertly guided through a series of analogies and examples through a complex subject until you arrive at an incredible payoff in perfectly understandable terms.

I won't spoil the surprise. But it'll just say I love how this proof works so, so much.

In the end it rests on the logic that if A then B but we know !B therefore !A. It proves that for something to be true, then something else which we _know_ to be false would then have to be true. Therefore that something must not be true. I love it.

<comment><USER16> I remember my professors saying proof by contradiction was very powerful. i guess they were right after all.

</comment></comment><comment><USER17> Can someone please explain how the math works out to 89%?

 _> > let's imagine two players, Alice and Bob, and a 3-by-3 grid. A referee assigns Alice a row and tells her to enter a 0 or a 1 in each box so that the digits sum to an odd number. Bob gets a column and has to fill it out so that it sums to an even number. They win if they put the same number in the one place her row and his column overlap. They're not allowed to communicate. Under normal circumstances, the best they can do is win 89% of the time._

<comment><USER18> Here the explanation and the picture describes the best strategy [https://en.wikipedia.org/wiki/Quantum_pseudo- telepathy#The_M...](https://en.wikipedia.org/wiki/Quantum_pseudo- telepathy#The_Mermin%E2%80%93Peres_magic_square_game)

</comment></comment><comment><USER3> Some practical questions:

a. What does this mean about Google's claim of quantum supremacy? [1] Does the new paper prove that quantum computers with entangled provers are more versatile than classical computers, because they can work in a larger problem space? Would that also mean that there is definitely such a thing as quantum supremacy, regardless of whether we've achieved it yet?

b. How does this affect CERN? That research institute is a melting pot of physicists, computer scientists, and mathematicians. This proof did not come from CERN, but I feel like CERN has the best resources to apply the proof. Need some entangled particles? Sure, let me just go downstairs to the LHC and pick up a few. Want to play a nonlocal game? Second door on your left. Need the Grid supercomputing network to verify your proof? You've got it. I hope that someone will be able to use this to reassure politicians that CERN is worth funding.

c. Does anyone know whether Tsirelson saw the proof (13 Jan) before he died (21 Jan), and what his reaction was?

I'm also really impressed at how Vidick & Ito, and Natarajan & Wright were working independently, and then joined forces to become a genius team. My gut feeling is that MIP* = RE is the E = MC^2 of quantum computing.

[1] [https://news.ycombinator.com/item?id=21332768](https://news.ycombinator.com/item?id=21332768)

<comment><USER19> what I gathered from it is that infinite quantum computers can't be approximated by any finite, no matter how unreasonably large, quantum computers. we're in no danger of possessing an infinite quantum computer, so probably not that many implications either google or CERN.

</comment></comment><comment><USER20> Isn't that animation at the top of the page just awesome?

<comment><USER21> I'm happy someone here mentioned it, I was entertained by it for some time!

</comment></comment><comment><USER22> So now when you get stuck on a hard problem, someone can actually prove that it's because you suck? Thanks science!

</comment><comment><USER23> In layman terms please?

</comment><comment><USER24> One of the authors of this paper (Thomas Vidick) is a prof in my department. Brilliant guy!

</comment><comment><USER11> If I understand it right, the proof shows the difference between a finite matrix of recursively enumerable operators and infinite matrix of non- recursive operators, is that about correct?

</comment><comment><USER25> wait, does that mean that Rice's theorem is wrong and machines can now solve nontrivial semantic problems?

<comment><USER26> No, from my reading, this uses the opposite, it uses the fact that the halting problem is unsolvable to show that MIP* cannot solve harder problems than RE, which are a class easier than nontrivial semantic questions and the halting problem.

<comment><USER27> I think you are mistaken. RE is the class that includes the halting problem.

<comment><USER27> I know its really bad form to complain about downvotes - but can i ask if people are disagreeing with me or if there is something else objectionable in my comment? If its the former, i'm confused as its trivially easy to google the definition of recursively enumerable, if its the latter I am honestly curious.

</comment></comment></comment></comment><comment><USER28> Slight tangent, but it seems to me that humans are not bounded by the halting problem like computers are. In other words, given a general algorithm to determine whether a program halts, I can always write a program that fools the algorithm. But I can't write a program that fools my brain. Ergo, human brains are not simply biological Turing machines like everyone seems to think?

<comment><USER29> The halting problem is that there is no algorithm possible that can answer, for all programs and all inputs, whether that program with that input will halt.

Here is my program:

        def fool(input):
            while input:
                pass

The input given to the program is your answer as to whether it halts given that input.

That's the gist of the proof that the halting problem is unsolvable. Whatever the algorithm or method is used to answer the problem, you can take that method and "embed" it into the program to be verified, and invert the answer.

The halting program doesn't say you can't answer for many or even most programs and inputs, it just says there'll be at least one counter-example.

<comment><USER30> That's not really how it works, though. You could imagine writing an AI program that can read this program, figure out that it halts on the truthiness of the input, and handles this case flawlessly.

The real proof is a bit of a head scratcher. Imagine we created such a function, doesHalt, that can read any program's source code and always figure out if the program will halt. This program can solve the halting problem -- it always produces a solution, either a True or a False. Feed it your fool program, it can always solve it, for any arbitrary input.

So what happens if we run create this little head scratcher function, that takes no input:

      def headScratcher():
        if doesHalt(headScratcher):
          while 1: pass

This program halts if doesHalt() says it doesn't halt, and does not halt if doesHalt says it does halt. These are both contradictions -- proving that such a doesHalt function cannot actually exist.

</comment></comment></comment><comment><USER31> I'm not a physicist or mathematician, but I tried to reduce this article to a basic level to see if I understood it. Maybe this will be helpful to someone else:

Assumptions in CS complexity theory:

1\. Turing showed that you can't tell ahead of time if a program will run forever or eventually stop. This is the halting problem. It proves that some problems are impossible to solve with computers even with infinite memory and CPU.

2\. But you can often verify if an answer to a problem is correct more easily than solving the problem itself.

3\. But some problems are so difficult that even verifying if an answer is correct is seemingly impossible - like verifying some properties of an infinite graph of nodes. This is because the graph could be infinitely large, so you could never have enough memory in your computer to even number the nodes, let alone inspect them.

4\. Sometimes if you can't verify the solution with your own computer, you can use your computer to interrogate a more power computer to indirectly verify it. You ask inter-related questions that are easy to verify to the more power computer (called the "prover") about it's solution. If you get consistent answers back more frequently then chance, you can assume the entire solution is correct.

5\. Going even further, you could have two 'prover' computers and ask inter- related questions to both about the same solution. Since you can now cross- check their answers against each other, you are able to indirectly verify even more complex solutions. This is like a detective checking the stories if different witnesses against each other.

tl;dr - Some problems are unsolvable, but it may or may not be possible to verify a single solution. Computer scientists want to quantify the complexity of verifying these solutions.

Assumptions in Quantum Physics:

1\. Particles can be "entangled". This means that if you observe one particle, some other particle somewhere else will exhibit the exact same state change, as though they are connected by a mysterious communication channel.

2\. This is super weird. Einstein thought it was so weird that he thought they must be missing something in their understanding.

3\. Physicists created two separate mathematical models to describe how entanglement works: (A) the Tensor Product model, using finite dimension matrices and (B) the Commuting Operator mode, using infinite dimension matrices

tl;dr - Quantum Physics is so weird that they came up with two mathematical models for entanglement

Assumptions in Mathematics:

1\. Because physicists said that the same physical property (entanglement) could be described either with infinite matrices or finite matrices, maybe you can approximate an infinite matrix using a finite matrix. This idea is the 'Connes embedding conjecture'.

2\. If finite and infinite matrices are actually interrelated by the Connes embedding conjecture, maybe it means that solving one means you solved the other.

tl;dr - The two quantum physics models inspired mathematicians to conjecture about the relationship between finite and infinite matrices

Back to Physics:

1\. To prove that quantum entanglement exists in real life and isn't just a math mistake, they came up with the idea of a "nonlocal game". You set up a seemingly-random test where two 'players' make guesses and the goal is to have them hit on the same guess more often than chance. If they win higher than chance, you can assume they are entangled.

2\. Using those tests, they showed that quantum entanglement is real.

Back to Computer Science:

1\. Computational complexity is not just a theory. "The resources that computers need to solve and verify problems — time and memory — are fundamentally physical." If you change the rules physics, you can change the rules of computer science. Our understanding of quantum entanglement as a real thing thus changes the rules of what a computer can do.

2\. If two entangled particles can behave in a correlated manner, you can (in theory) use that coordination to verify the solution to harder problems by using them as two "provers". For example, you could have each particle randomly pick a node in your infinite graph and inspect a different edge. But since they are entangled, the two particles always pick the same node. That means you can use them to indirectly inspect an infinite graph and verify a previously unverifiable solution.

New CS discovery in the paper:

1\. Entangled provers allow you to verify solutions to the unsolvable halting problem. That implies that you can also verify the solution to any problem easier than the halting problem using quantum particles.

2\. This neat and re-writes the rules of CS complexity, but at a glance appears not very interesting to other fields.

New Implication for Physics:

1\. Wait a sec! Since the problem you are verifying itself is unsolvable, this implies the two mathematical models of quantum entanglement are NOT equivalent (more details in article).

New Implication for Math:

1\. This means the Connes embedding conjecture (which said we can estimate an infinite-dimension matrix from from a finite dimension matrix) is also definitely FALSE.

So in the process of computer scientists trying to clarify the bounds of computational complexity theory, they accidentally re-wrote the rules of quantum physics and invalidated a major mathematical assumption. But the CS researchers aren't physicists or classical mathematicians, so they don't even claim to fully understand the cross-discipline implications of what they discovered.

<comment><USER32> > 2\. But you can often verify if an answer to a problem is correct more > easily than solving the problem itself.

Not necessarily. Or rather, we don't know that's actually the case for the most important example - machines which work in time polynomial in the length of their input (P vs. NP).

</comment></comment><comment><USER33> I am impressed by Quanta's dedication to trying to make cutting-edge theoretical mathematics comprehensible. I wouldn't say I succeeded in understanding this, but I feel like I got 10% of the way there.

<comment><USER34> I feel the opposite. They are so dedicated to making math sizzly that their articles are full of hype paragraphs of "mathiness" to get you excited without learning much. The clickbait headline, the intricate animation of the clickbait headline(!), the paragraphs of "human interest" goop. The worst part is that I know they bury a nugget of actual math in there, but I get exchausted trying to find it.

<comment><USER35> > nugget of actual math

If you are seriously looking for a nugget I would suggest trying to understand the nonlocal game example (which was hidden in the write up)

"But first, to see how the games work, let's imagine two players, Alice and Bob, and a 3-by-3 grid. A referee assigns Alice a row and tells her to enter a 0 or a 1 in each box so that the digits sum to an odd number. Bob gets a column and has to fill it out so that it sums to an even number. They win if they put the same number in the one place her row and his column overlap. They're not allowed to communicate.

Under normal circumstances, the best they can do is win 89% of the time. But under quantum circumstances, they can do better.

Imagine Alice and Bob split a pair of entangled particles. They perform measurements on their respective particles and use the results to dictate whether to write 1 or 0 in each box. Because the particles are entangled, the results of their measurements are going to be correlated, which means their answers will correlate as well — meaning they can win the game 100% of the time."

These notes might help to understand the basic idea: [https://www.scottaaronson.com/qclec/14.pdf](https://www.scottaaronson.com/qclec/14.pdf) In particular, after understanding why the best they can is win 89% on normal circumstances, the easier examples at the beginning of the notes provide intuition of how a quantum strategy might help for the 3-by-3 grid game. Edit: also see the write up by ahelwer below.

<comment><USER36> > Imagine Alice and Bob split a pair of entangled particles. They perform > measurements on their respective particles and use the results to dictate > whether to write 1 or 0 in each box.

Why not just imagine Alice tells Bob how she's going to choose what to write in the boxes? That works 100% of the time too.

I don't see a distinction between "Alice and Bob communicate" and "a pair of entangled particles gives Alice and Bob a piece of shared information that, by prior arrangement, they both interpret in the same way."

<comment><USER37> Yep, I quite literally came here to post this. It seems like exactly the kind of "not giving enough information to _really_ understand a topic" that the OP was complaining about.

If communication really needs to be forbidden, just let them agree on an RNG beforehand and share a seed. This _seems_ to eliminate any quantum magic involved, which suggests I don't really understand the problem, which suggests that they haven't really explained it.

<comment><USER35> Suppose that Alice and Bob share a seed to a RNG before the game starts.

Can you explain how this will allow them to always win the game?

<comment><USER37> No, but as I said in my parallel comment, I don't understand how you can do any _better_ than having an infinite amount of pre-shared information without actually communicating. If you can explain that, great (I really would be interested), but the important thing here is that without explaining it the article is kind of flawed.

<comment><USER38> I'll make an attempt, though I am by no means a domain expert. As I said in another comment, Alice doesn't know which column is Bob's column, and Bob doesn't know which row is Alice's row. Bell-like inequalities allow something interesting to happen: Alice and Bob can measure a qubit at different "basis angles" such that the phase difference in their basis angles is reflected in the correlation of what outputs they observe from the qubit. You can't do this classically; what Alice does with a pre-shared bit and her row and what Bob does with the pre-shared bit and his column, form independent random variables.

It may help to point out that (someone correct me if I'm wrong here...) this only works if _both_ Alice and Bob are able to use their hidden information to choose the bases they're using to measure the qubit; if they were stuck with measuring at pre-determined angles, this trick doesn't work.

<comment><USER36> OK, so if I'm understanding this right - when you give them a pair of entangled particles, they can each do some stuff to their particle to determine what the other party is going to do. How is this not communication?

<comment><USER39> I think (but IANAP) the answer is in two parts: (1) you can't intentionally send a message—it's like asking whether ancient civilisations are communicating with archaeologists, to which the answer is surely "only metaphorically"; and (2) even if it is communication in some sense, it's still surely surprising, no?

<comment><USER36> Point 1) matches my lay understanding of quantum entanglement; information is transferred somehow between the entangled particles but not in a way that we can use. So if this new thing IS communication via entanglement (and I can't see how it's not, given the description) then that's huge, and opens the door to all sorts of interesting things.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER40> 081499

</comment><comment><USER41> So is this a proof for P=NP or something else entirely? I found article much too dense to understand fully

<comment><USER42> It's seen as a stepping stone towards P vs NP.

<comment><USER43> In what way ?

</comment></comment></comment><comment><USER44> In high school our math teacher introduced a problem that could not be solved, which involved a TV-show game where the contender would choose one of 3 doors, and if there was something behind it, the contender would win it. But the show host would remove one of the doors without something behind it, and ask the contender if he/she would like to switch door.

I simply simulated the game on a computer one million times which revealed that changing the door after the host removed a empty one had a 66% probability of winning. (rather then 50%) but the teacher wouldn't believe me...

<comment><USER45> This is a famous problem and the solution is not contested.

<comment><USER46> I'd rather say that the solution is _constantly_ contested by people who can't shake off their intuition.

<comment><USER47> To be fair, the problem is often badly posed. The host always reveals a goat, and this is crucial information, but people often fail to make it clear. If the host chose randomly and just happened to reveal a goat, the solution would be the 'intuitive' one.

<comment><USER48> No, I don't think that's accurate. In the scenario you pose, sticking and switching have an equal reward, so both are valid solutions.

<comment><USER47> > sticking and switching have an equal reward

Right, and this is the intuitive solution. Nobody argues that switching reduces your chance of success; the split is over whether it increases it to 2/3 or leaves it at 1/3.

(The problem statement ends with 'Is it to your advantage to switch your choice?' The right answer under the intended assumption about the host is 'yes', but the intuitive answer is 'no, it makes no difference'.)

<comment><USER47> Sorry, I shouldn't have said 'increases it to 2/3 or leaves it at 1/3'. If he picks randomly and reveals a goat, the probability that your original choice of door is a winner is now 1/2, as is the probability that the remaining door is a winner.

</comment></comment></comment></comment></comment></comment></comment><comment><USER49> > The new proof establishes that quantum computers that calculate with > entangled quantum bits or qubits, rather than classical 1s and 0s, can > theoretically be used to verify answers to an incredibly vast set of > problems.

LOL this was the original promise of Quantum Computers. I would think a proof would be a quantum computer that actually delivers on that promise.</comment>