sympy/sympy — pull request #8706 by aktech (2014-12-27 17:45:59+00:00)
Title: Add is_real functionality for factorial Fix issue #8658

Factorial function don't have the is_real functionality to check this Assumption.
factorial(x) is not known to be real when 'x' is non-negative.

With this PR, user can check if the given factorial is real or not.
Fixes #8658