sympy/sympy — pull request #8327 by zanzibar7 (2014-10-26 22:38:13+00:00)
Title: Add rewrite rules for jump functions

- rewrite Abs and sign as Heaviside
- rewrite Heaviside as sign
- rewrite of Max and Min in terms of several Heavisides

(a prequal to my separate pull request on integrating Heavisides -- get the easy stuff out of the way first)