Theorem fndmi

Description: The domain of a function. (Contributed by Wolf Lammen, 1-Jun-2024)

	Ref	Expression
Hypothesis	fndmi.1	⊢ 𝐹 Fn 𝐴
Assertion	fndmi	⊢ dom 𝐹 = 𝐴

Proof

Step	Hyp	Ref	Expression
1		fndmi.1	⊢ 𝐹 Fn 𝐴
2		fndm	⊢ ( 𝐹 Fn 𝐴 → dom 𝐹 = 𝐴 )
3	1 2	ax-mp	⊢ dom 𝐹 = 𝐴