How to define another proof environment, say, for the "Proof of lemma"? Also, how to make it without the qed box? (I need one with qed box, and another one without qed box.)
I'm using amsbook document class with amsthm package.
if you're using
to get a heading "Proof of lemma", use
to omit the box, just before
(this does not persist after the proof ends.)
both features are described in the manual: