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.