Subject: topology list
From: muro@mpim-bonn.mpg.de
Date: Fri, 26 Aug 2005 16:20:23 +0200

These are 2 questions for the topology discussion list:

Does the Friedlander-Milnor conjecture hold for orthogonal groups 
$O(n)$ (over the reals and for $n>2$) and second cohomology with mod 2 
coefficients $H2(-,\Z/2)$? I've only managed to find partial answers 
to this question in the literature.

Let $G$ be a Lie group, $A$ a finite abelian group 
(I'm thinking of $\Z/2$) and suppose that $G$ acts trivially on $A$. 
Let $BG$ be the classifying spaces. Which is the relation betweem 
$H2(BG,A)$ and the central extensions of Lie groups $A-->H-->G$?