Theorem fdmi

Description: Inference associated with fdm . The domain of a mapping. (Contributed by NM, 28-Jul-2008)

	Ref	Expression
Hypothesis	fdmi.1	$$⊢F:A⟶B$$
Assertion	fdmi	$$⊢\mathrm{dom}F=A$$

Proof

Step	Hyp	Ref	Expression
1		fdmi.1	$$⊢F:A⟶B$$
2		fdm	$$⊢F:A⟶B\to \mathrm{dom}F=A$$
3	1 2	ax-mp	$$⊢\mathrm{dom}F=A$$