Bourbaki

Proposition 9

Tag 0E0D, permanent. Cite it as [Bourbaki, Tag 0E0D].

Algebra, chapter X, § 7. Produit de composition

The following diagram, where γθ(α)=θ∘α\gamma_\theta(\alpha) = \theta \circ \alpha, is commutative:

Hk(HomgrA(N,E′))→Hk+n(HomgrA(1N,σ))Hk+n(HomgrA(N,E))↓φk(N,E′)↓φk+n(N,E)ExtAk(N,M′)→γθExtAk+n(N,M) \begin{array}{ccc} H^k(\mathrm{Homgr}_A(N, E')) & \xrightarrow{H^{k+n}(\mathrm{Homgr}_A(1_N, \sigma))} & H^{k+n}(\mathrm{Homgr}_A(N, E)) \\ \downarrow \varphi^k(N, E') & & \downarrow \varphi^{k+n}(N, E) \\ \mathrm{Ext}_A^k(N, M') & \xrightarrow{\gamma_\theta} & \mathrm{Ext}_A^{k+n}(N, M) \end{array}

This is proved in a way analogous to Proposition 8.

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

Nothing.

Translated with machine help, not yet reviewed by a person.