Let $M$ be a finite CW-complex. Let $F$ be a finite rank local system over $M$ with coefficients in any field. Is it true that $dim(H^k(M,F))$$\dim(H^k(M,F))$ is at most the number of $k$-cells times $rank(F)$$\operatorname{rank}(F)$?
If $F$ is the trivial local system then this result is proven in almost any standard textbook in topology (or at least immediately follows from there). I believe that it should be true in the above generality and would be happy to have a reference.