Bourbaki

Exercise 20, § 4

General Topology, X, p. 60

Let XX be a completely regular space. Now prove that every subset of βX\beta X which is a countable intersection of non-empty open sets meets XX. Deduce that in order that βX\beta X be meagre in itself (resp. a Baire space), it is necessary and sufficient that XX be meagre in itself (resp. a Baire space).

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Machine translation of the English, by gpt-5-6-mini. Not checked by a person. That model is a cut down version of the one the rest of this language was written by.