Definition
If G is a finite group and A a G-module, then there is a natural map N from H0(G,A) to H0(G,A) taking a representative a to Σ g(a) (the sum over all G-conjugates of a). The Tate cohomology groups are defined by
- for n≥ 1.
- quotient of H0(G,A) by norms
- quotient of norm 0 elements of H0(G,A) by principal norm 0 elements
- for n≤ −2.
Read more about this topic: Tate Cohomology Group
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