sympy/sympy — pull request #8307 by dqnykamp (2014-10-24 22:04:48+00:00)
Title: Don't add parentheses when splitting symbols to objects in dictionaries.

Crucial when object is a function so that it is not multiplied by its argument.

c.f. https://groups.google.com/forum/#!topic/sympy/MKhZdgB_Sg4