Bourbaki

Corollary 2

Tag 023Q, permanent. Cite it as [Bourbaki, Tag 023Q].

Topologie algébrique, chapter IV, § 5. Théorème de van Kampen

Suppose moreover that the arcwise connected components of Y are simply arcwise connected. The homomorphism μ:F(J−T)→π1(\mu: F(J-T)\rightarrow \pi_1(Cone(f),s)(f), s) is then an isomorphism.

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-5-6-mini, gpt-5-6, gpt-5.4, 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.