Bourbaki

Corollary 2

Tag 0BF4, permanent. Cite it as [Bourbaki, Tag 0BF4].

General Topology, chapter II, § 3. Complete spaces

Let II be a directed set which has a countable cofinal subset. Let (Xα,fαβ)(X_\alpha, f_{\alpha \beta}) and (Xα′,fαβ′)(X'_\alpha, f'_{\alpha \beta}) be two inverse systems of sets indexed by II, and for each α∈I\alpha \in I let uα:Xα→Xα′u_\alpha : X_\alpha \to X'_\alpha be a mapping, such that the uαu_\alpha form an inverse system of mappings. Let u=lim←⁡uαu = \varprojlim u_\alpha. Let x=(xα′)x = (x'_\alpha) be an element of

X′=lim←⁡Xα′ X' = \varprojlim X'_\alpha

which satisfies the following condition: for each α∈I\alpha \in I there is an index β≥α\beta \geq \alpha such that for all γ≥β\gamma \geq \beta we have fαγ(u‾γ−1(xγ))=fαβ(u‾β−1(xβ′))f_{\alpha \gamma}(\overline{u}_\gamma^{-1}(x_\gamma)) = f_{\alpha \beta}(\overline{u}_\beta^{-1}(x'_\beta)). Then there is an element x∈Xx \in X such that u(x)=x′u(x) = x'.

Apply Theorem 1 to the inverse system of sets u‾α−1(xα′)\overline{u}_\alpha^{-1}(x'_\alpha), each carrying the discrete uniformity.

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

Transcribed from the printed volume. Not translated.