sympy/sympy — pull request #958 by goodok (2012-01-12 01:31:43+00:00)
Title: issue 2983: fix exception for 'Max(x, 1)*Max(x, 2)'.

This fix the exceptions like

>>> Max(x, 1) * Max(x, 2)
TypeError: cannot compare sets using cmp(

>>> Or(x, z) * Or(x, y)
TypeError: cannot compare sets using cmp(

See [Issue 2983](http://code.google.com/p/sympy/issues/detail?id=2983)