One of the aims of this article is to investigate the solvability and unsolvability conditions for fractional cohomological equation , f = g, on Tn. We prove that if f is not analytic, then fractional integro-di, erential equation I1, ,t D,x u(x,t) + iI1, ,x D,t u(x,t) = f(t) has no solution in C1(B) with 0 < ,,1. We also obtain solutions for the space-time fractional heat equations on S1 and Tn. At the end of this article, there are examples of fractional partial di, erential equations and a fractional integral equation together with their solutions.