Subject: Re: two postings From: Ralph Cohen Date: Mon, 21 Nov 2005 12:08:22 -0800 With regard to the discussion of the integral cohomology of BO(n) and BSO(n), there were two papers published in the early 1980's giving explicit calculations of these. One was by Ed Brown, and the other by Mark Feshbach. Below are the MathSciNet references. -Ralph Cohen MR0652459 (83d:55015) Brown, Edgar H., Jr. The cohomology of $B {\rm SO}\sb{n}$ and $B{\rm O}\sb{n}$ with integer coefficients. Proc. Amer. Math. Soc. 85 (1982), no. 2, 283--288. (Reviewer: R. E. Stong) 55R40 MR0703281 (85b:55025) Feshbach, Mark The integral cohomology rings of the classifying spaces of ${\rm O}(n)$ and ${\rm SO}(n)$. Indiana Univ. Math. J. 32 (1983), no. 4, 511--516. (Reviewer: R. E. Stong) 55R40