🚀 go-pugleaf

Hi,
     This is another in a series of questions orignated from my secretary.
Within LaTeX, is it possible to change the left margin temporarily and
still retain the option (within this new smaller page) to use eqnarray,
array, etc.?  This comes up when writing proofs of results, where one says

Thm  blah blaah .....
Proof:
(==>) proof proof proof proof proof proof proof proof proof proof 
      proof proof proof proof proof proof proof proof proof proof proof
       
             eqnarray stuff
     proof proof proof proof proof proof proof proof proof proof  QED

(<==) proof proof proof proof proof proof proof proof proof proof 
      proof proof proof proof 
      
            array stuff                                       QED



Thanks, 
Lones Smith
MIT economics

BTW  A related desire is to be able to hfill within the  eqnarray* or array
     environments.    This was implicitly done in my above proof, where
     QED was on the same line as array stuff.