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Kevin Walker comments on "Four closely related questions -- how best to group them?" (14094)
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14094#Comment_14094
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14094#Comment_14094Tue, 12 Apr 2011 15:35:41 -0700Kevin WalkerTom Church comments on "Four closely related questions -- how best to group them?" (14092)
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14092#Comment_14092
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14092#Comment_14092Tue, 12 Apr 2011 12:37:07 -0700Tom ChurchDL comments on "Four closely related questions -- how best to group them?" (14091)
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14091#Comment_14091
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14091#Comment_14091Tue, 12 Apr 2011 10:41:51 -0700DLKevin Walker comments on "Four closely related questions -- how best to group them?" (14090)
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14090#Comment_14090
http://mathoverflow.tqft.net/discussion/1009/four-closely-related-questions-how-best-to-group-them/?Focus=14090#Comment_14090Tue, 12 Apr 2011 09:26:02 -0700Kevin Walker (1) What's a good reference/citation for the cohomology of the Eilenberg-MacLane space $K(G, 2)$? (I'm really just interested in the degree five-or-less cohomology. Recall that $\pi_i(K(G, 2)) = G$ if $i=2$ and is trivial otherwise.)

(2) What's a good reference/citation for explicit constructions of $K(G, 2)$?

(3) The finite cell complex $X$ (details omitted here) has $\pi_2 = G$. Is there a reference for the 4- and 5-cells one needs to add to $X$ to make it into a $K(G, 2)$? (Of course one also needs to add higher cells, but I'm not interested in those.)

(4) The finite cell complex $Y$ (details omitted here; not the same as $X$ above) has $\pi_2 = G$. Is there a reference for the 4- and 5-cells one needs to add to $Y$ to make it into a $K(G, 2)$?

My first thought was to let (1) be a stand-alone question and lump (2), (3) and (4) together. But if there's a consensus here in favor of some other way of grouping them then I'm happy to follow that. ]]>