Lemma 1
Tag 0BON, permanent. Cite it as [Bourbaki, Tag 0BON].
General Topology, chapter III, § 7. Inverse limits of topological groups and rings
Under the hypotheses of Proposition 2, if is any closed subset of we have .
For is the intersection of the sets where runs through the neighbourhood filter of [ 3, no. 1, formula (1)], and every neighbourhood of contains an ; whence the result, since .
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.