One posting: I would have handled this elementary question myself, but was not sure about a reference for nontrivial local coefficients. Does anyone know a reference that would handle this entire question...DMD _________________________________________________________ Subject: Question for the list! From: Xu an Zhao Date: Thu, 25 Nov 2004 09:56:06 +0800 (CST) Could you please post the following question on the topology list? Let $X=RP^{\infity}$ is the infinity dimensional real projective space, what is the cohomology of $H^*(X,Z)$ and $H^*(X,Z_q)$, especially how to compute their multiplications strcture, where $Z,Z_q$ is the Local coefficient on $X$(trivial or nontrival) and $q=p^r$ for odd prime number $p$. Best regards Zhao Xu an