～てない - ambiguity between ている and てある


> 手を上げてない人は私だけです。

上げてない is the negative form of てある right? Most people would omit the い in ている.
So for me it is hard to differentiate if てある or ている is used since both sounds
the same (negative only). So how to differentiate? From writing the ている is
ていない and てある is てない. In writing you can't omit the い in ている／ていない right?

手をあげていない means: not raising hand.  
手をあげてない means: hand has not been raised.

Are these correct? Is the meaning of the first sentence like this? the person
whose hand has not (yet) been raised is only me. Which can be simplified into
: the person who is not raising their hand is me. If I change ない into いない...
Then it would roughly translate as (hand is still rising ; still in motion ;
not yet been raised) right? Because in english "raising our hand" usually
means the state after the action of "raise" is completed (hand is constant in
the air and not going any higher). Unlike "falling" that usually means the
ongoing action of "fall" and not the state after the action of "fall" is
completed. Feel free to correct any facts conveyed here.




Generally I think you can tell by the subject.  
(Very similar to the conversation between yourself and oldergod above)

上げてる (who or what?) ⇒ 私 ＝ 上げて **い** る

Other examples of ambiguity resolved by identifying the subject/actor:

> 置いてない

  * 「私はそこに置いてないよ」 - Subject/Actor is 私, so this must mean 置いて **いない**
  * 「お肉は冷蔵庫に置いてると思う」 - Subject is probably お肉, so this must mean 置いて **ありません**

> 開けてない

  * 「私は窓開けてないよ」 - Subject/Actor is 私, so this must mean 開けて **いない**
  * 「窓は開けてないと思う」 - Subject is probably 窓, so this must mean 開けて **ありません**

