Bourbaki

Corollary

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

Topologie algébrique, chapter III, § 3. Groupoïde de Poincaré

Let aa be a point of X and let J be the set of i∈Ii\in I such that a∈Aia\in A_i. The canonical homomorphism

lim⟶i∈Jπ1(Ai,a)→π1(X,a)\longrightarrow_{i\in J}\pi_1(A_i, a)\rightarrow \pi_1(X, a)

is bijective.

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, against glossary version 34. Not checked by a person.