Metamath Proof Explorer


Theorem ffunOLD

Description: Obsolete version of ffun as of 10-Jun-2026. (Contributed by NM, 3-Aug-1994) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion ffunOLD F : A B Fun F

Proof

Step Hyp Ref Expression
1 ffn F : A B F Fn A
2 fnfun F Fn A Fun F
3 1 2 syl F : A B Fun F