Definition 2

Tag 03QV, permanent. Cite it as [Bourbaki, Tag 03QV].

Theory of Sets, chapter III, § 3. Equipotent sets. Cardinals

The set $\tau_Z(\mathrm{Eq}(X, Z))$ is called the cardinal of X (or the power of X) and is written $\mathrm{Card}(X)$ .

Since $\mathrm{Eq}(X, X)$ is true, $\mathrm{Card}(X)$ is equipotent to X (Chapter I, § 4, Scheme S5). We have therefore proved the following result :

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.

Cited by

Nothing.

Cites

Chapter I, § 4