Bourbaki

Proposition 15

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

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

The image of a path in a separated topological space is a compact, metrizable, connected and locally connected by arcs topological space.

Let X be a separated topological space and c:I→Xc:\mathbf{I}\rightarrow X a continuous mapping. Let R denote the equivalence relation c(s)=c(t)c(s) =c(t) in I\mathbf{I}. The topological space c(I)c(\mathbf{I}) is separated (TG, I, p. 63, cor. 1), the space I/R\mathbf{I}/R is quasi-compact (TG, I, p. 62, th. 2), hence the bijection I/R→c(I)\mathbf{I}/R\rightarrow c(\mathbf{I}) deduced from cc is a homeomorphism (TG, I, p. 63, cor. 2). Consequently, the space c(I)c(\mathbf{I}) is compact, metrizable (TG, IX, p. 22, prop. 17), connected (TG, I, p. 82, prop. 6) and locally connected by arcs (III, p. 261, prop. 8).

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-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.