Corollary 3
Tag 0B43, permanent. Cite it as [Bourbaki, Tag 0B43].
General Topology, chapter I, § 6. Filters
The ordered set of all filters on a non-empty set is inductive.
For every linearly ordered set of filters on satisfies the condition of Corollary 2 of Proposition 1, since the sets all belong to the same by hypothesis, and we can apply .
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.