Metamath Proof Explorer

Theorem fdmOLD

Description: Obsolete version of fdm as of 29-May-2024. (Contributed by NM, 2-Aug-1994) (Proof modification is discouraged.) (New usage is discouraged.)

		Ref	Expression
	Assertion	fdmOLD	$⊢ F : A ⟶ B \to dom F = A$

Proof

Step	Hyp	Ref	Expression
1		ffn	$⊢ F : A ⟶ B \to F Fn A$
2		fndm	$⊢ F Fn A \to dom F = A$
3	1 2	syl	$⊢ F : A ⟶ B \to dom F = A$