Commit 2025-07-02 03:33 fcbb8034
View on Github →feat(RepresentationTheory/GroupCohomology): long exact sequences (#25872)
Given a commutative ring k and a group G, this PR shows that a short exact sequence of k-linear G-representations
0 ⟶ X₁ ⟶ X₂ ⟶ X₃ ⟶ 0 induces a short exact sequence of complexes
0 ⟶ inhomogeneousCochains X₁ ⟶ inhomogeneousCochains X₂ ⟶ inhomogeneousCochains X₃ ⟶ 0.
Since the cohomology of inhomogeneousCochains Xᵢ is the group cohomology of Xᵢ, this allows us to specialize API about long exact sequences to group cohomology.