<div class="floatright"><a href="https://en.wikiversity.org/wiki/User:Lipedia/hat#Reverse_binary" title="The subsets of V_4 are numbered in reverse binary order."><img alt="The subsets of V_4 are numbered in reverse binary order." src="https://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Little-endian_binary.svg/100px-Little-endian_binary.svg.png" decoding="async" width="100" height="179" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Little-endian_binary.svg/150px-Little-endian_binary.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Little-endian_binary.svg/200px-Little-endian_binary.svg.png 2x" data-file-width="819" data-file-height="1467"></a></div>
<p><a href="https://en.wikipedia.org/wiki/Hereditarily_finite_set" class="extiw" title="w:Hereditarily finite set">V<sub>4</sub></a> =  <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">P</a>^4(<a href="https://en.wikipedia.org/wiki/empty_set" class="extiw" title="w:empty set">{}</a>) = <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">P</a>( <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">P</a>( <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">P</a>(<a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">P</a>(<a href="https://en.wikipedia.org/wiki/empty_set" class="extiw" title="w:empty set">{}</a>)))) is the <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">powerset</a> of the <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">power set</a> of the <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">power set</a> of the <a href="https://en.wikipedia.org/wiki/power_set" class="extiw" title="w:power set">power set</a> of the <a href="https://en.wikipedia.org/wiki/empty_set" class="extiw" title="w:empty set">empty set</a>.
</p><p>Compare: <a href="//commons.wikimedia.org/wiki/File:Elements_of_P%5E4(empty_set)_in_Hasse_diagram.svg" class="mw-redirect" title="File:Elements of P^4(empty set) in Hasse diagram.svg">File:Elements of P^4(empty set) in Hasse diagram.svg</a>
</p><p>The number of rings in the representation of each number is described by <span style="white-space:nowrap"><a href="https://en.wikipedia.org/wiki/On-Line_Encyclopedia_of_Integer_Sequences" title="Sloane's"><img alt="Sloane's" src="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/OEISicon_light.svg/11px-OEISicon_light.svg.png" decoding="async" width="11" height="15" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/OEISicon_light.svg/17px-OEISicon_light.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/OEISicon_light.svg/22px-OEISicon_light.svg.png 2x" data-file-width="409" data-file-height="556"></a> <a href="//oeis.org/A116549" class="extiw" title="oeis:A116549">A116549</a></span>.
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In this version the rings containing an even number of rings are blue and those containing and odd number are red.
<table><tbody><tr><td style="padding: 15px;"><a href="//commons.wikimedia.org/wiki/File:Watchduck.svg" class="image"><img alt="Watchduck.svg" src="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Watchduck.svg/40px-Watchduck.svg.png" decoding="async" width="40" height="46" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Watchduck.svg/60px-Watchduck.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Watchduck.svg/80px-Watchduck.svg.png 2x" data-file-width="703" data-file-height="806"></a>
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<td><a href="//commons.wikimedia.org/wiki/User:Watchduck" title="User:Watchduck">Watchduck</a><br><span style="color: gray; font-size: 80%;">You can name the author as "T. Piesk", "Tilman Piesk" or "Watchduck".</span>
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<span class="int-own-work" lang="en">Own work</span>