Corollary 2
Tag 01Q4, permanent. Cite it as [Bourbaki, Tag 01Q4].
Topologie algébrique, chapter I, § 4. Revêtements
Let B be a topological space and A a subspace of B. Suppose that the spaces A and B are locally connected and that the pair has property (PCV) of I, p. 37. Let E and be coverings of B, and let us denote by and their projections. Let
be an A-morphism ( resp. an A-isomorphism). Then there exists a neighbourhood U of A in B and a U-morphism ( resp. a
U-isomorphism) such that .
Let us retain the notation of corollary 1. By that same corollary, an A-morphism is identified with a section above A of the étale space associated with . By the hypothesis made on the pair and lemma 3 of I, p. 39, there exists an open neighbourhood U of A in B and a continuous section of above U extending . This section is identified with a U-morphism extending .
The case where is an A-isomorphism is treated analogously by considering, in place of the sheaf , the sheaf .
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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