Corollary

Tag 0B2H, permanent. Cite it as [Bourbaki, Tag 0B2H].

General Topology, chapter I, § 4. Product of topological spaces

The section $A(x_1)$ of an open (resp. closed) set $A$ of the product $X_1 \times X_2$ at an arbitrary point $x_1 \in X_1 (*)$ is open (resp. closed) in $X_2$ .

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

Cited by

Proposition 5, § 4
Corollary 1, § 1

Cites

Nothing.