Bourbaki

Proposition 2

Tag 01O6, permanent. Cite it as [Bourbaki, Tag 01O6].

Topologie algébrique, chapter I, § 3. Faisceaux

The mapping jFj_{\mathscr{F}} is the inverse B-isomorphism of eFe_{\mathscr{F}}.

For U∈B,s∈F(U)U\in \mathscr{B},s\in \mathscr{F}(U) and x∈Ux\in U, one has by definition of jF:j_{\mathscr{F}}:

jF([U,s,x])=[U,σF(U,s),x] j_{\mathscr{F}}([U, s, x]) = [U, \sigma_{\mathscr{F}}(U, s), x]

whence eF(jF([U,s,x]))=σF(U,s)(x)=[U,s,x]e_{\mathscr{F}}(j_{\mathscr{F}}([U, s, x])) =\sigma_{\mathscr{F}}(U, s)(x) = [U, s, x]. This proves the proposition.

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

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Cites

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Machine translation of the English, by gpt-5.4, gpt-5-6-mini, gpt-5-mini, against glossary version 34. Not checked by a person. That model is a cut down version of the one the rest of this language was written by.