Bourbaki

Proposition 9

Tag 01X7, permanent. Cite it as [Bourbaki, Tag 01X7].

Topologie algébrique, chapter III, § 2. Homotopie et chemins

The product of a family of locally path-connected spaces, connected with the exception of a finite number of them, is locally path-connected.

Let (Xj)j∈J(X_j)_{j\in J} be a family of locally path-connected spaces which are connected, with the exception of a finite number of them. Let x=x= (xj)j∈J(x_j)_{j\in J} be a point of the product space X = ∏j∈JXj\prod_{j\in J}X_j. By assumption, a fundamental system of neighbourhoods of xx in X consists of sets of the form V=∏j∈JVjV =\prod_{j\in J}V_j where, for every j∈Jj\in J, VjV_j is a path-connected neighbourhood of xjx_j in XjX_j and where Vj=XjV_j= X_j except for a finite set of indices j∈Jj\in J (TG, I, p. 24). These sets being path-connected (III, p. 260, prop. 6), X is locally path-connected.

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.

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Cites

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Machine translation of the English, by gpt-5-6-mini, gpt-5-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.