sympy/sympy — pull request #7296 by mrocklin (2014-03-18 02:35:17+00:00)
Title: Matmul refine

Add a refine handler for MatMul objects. This is a prototype for what could become a larger system.

Motivating discussion at https://groups.google.com/forum/#!topic/sympy/9RLimQ7n0Ww