[texhax] theorem macros

[Grant WALKER]

Dear TeX users group

I am a fairly experienced LaTeX user with WinEdt but I am new to MacTex.   I have installed the MacTex distribution successfully (several times now!) and I am trying a short mathematical file.   The system cannot find any ' theorem' macros.  I am using amsart and the packages amsmath, amssymb, amsthm --- it does not complain that it cannot find these.  But it refuses to have anything to do with any spelling of 'theorem'.  I have tried 'Theorem" 'thm' etc but none of these work.   The equation, its arrays, fonts etc seem to work OK.   But where are the theorem macros hiding? 

I'd be grateful for any suggestions.

Grant Walker