Proposition 9
Tag 021H, permanent. Cite it as [Bourbaki, Tag 021H].
Topologie algébrique, chapter IV, § 2. Groupes de Poincaré des espaces délaçables
Let X be an unravelable topological space and let be a basis for the topology of X. For every point of X, the cardinal of the group is bounded above by sup(Card(), Card()). In particular, the Poincaré group of a metric space of countable type and unravelable is countable.
In fact, the space endowed with the endpoint mapping is a connected covering of X whose fibre at is . The assertion then results from I, p. 40, th. 3.
Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.
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