Corollary 4

Tag 03N5, permanent. Cite it as [Bourbaki, Tag 03N5].

Theory of Sets, chapter III, § 6. Infinite sets

If $\mathfrak{a}$ and $\mathfrak{b}$ are two non-zero cardinals, one of which is infinite, we have $\mathfrak{a}\mathfrak{b} = \mathfrak{a} + \mathfrak{b} = \sup\,(\mathfrak{a},\,\mathfrak{b})$ .

This follows directly from Corollaries 2 and 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.

Cited by

Corollary 4, § 2
Proposition 8, § 3
Proposition 3, § 6

Cites

Nothing.