Metamath Proof Explorer


Theorem dffun6OLD

Description: Obsolete version of dffun6 as of 19-Dec-2024. (Contributed by NM, 9-Mar-1995) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion dffun6OLD Fun F Rel F x * y x F y

Proof

Step Hyp Ref Expression
1 nfcv _ x F
2 nfcv _ y F
3 1 2 dffun6f Fun F Rel F x * y x F y