sympy/sympy — pull request #2719 by Tempel (2013-12-30 20:55:15+00:00)
Title: Refactored sympy.core.relational.

Broke out logic from the Relational class into subclasses. Simplified the
logic without modifying it. Eliminated the helper functions, replacing with
aliases to the relevant classes. Added docstrings for Relational, Equality,
and Unequality.