sympy/sympy — pull request #1613 by smichr (2012-10-26 07:08:24+00:00)
Title: Pr1599

An error in powersimp was identified by the work happening in #1599. Basically, negative bases were being combined improperly so that `powersimp(I*sqrt(neg)) -> sqrt(-neg)` instead of `-sqrt(-neg)`. I thought all the power-rule errors were solved before...I can humbly say for sure that there is only one less now once this is committed.

I consider this a high priority issue but have not opened a new issue since it would (quickly) just be reclosed when this is committed.