Secondary Cohomology and k-invariants
نویسندگان
چکیده
For a triple (G,A, κ) (where G is a group, A is a G-module and κ : G → A is a 3-cocycle) and a G-module B we introduce a new cohomology theory 2Hn(G,A, κ;B) which we call the secondary cohomology. We give a construction that associates to a pointed topological space (X, x0) an invariant 2κ 4 ∈ 2H (π1(X), π2(X), κ; π3(X)). This construction can be seen a “3type” generalization of the classical k-invariant.
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