Theorem fdm

Description: The domain of a mapping. (Contributed by NM, 2-Aug-1994) (Proof shortened by Wolf Lammen, 29-May-2024)

	Ref	Expression
Assertion	fdm	$$⊢F:A⟶B\to \mathrm{dom}F=A$$

Proof

Step	Hyp	Ref	Expression
1		ffn	$$⊢F:A⟶B\to FFnA$$
2	1	fndmd	$$⊢F:A⟶B\to \mathrm{dom}F=A$$