Metamath Proof Explorer


Theorem oveq

Description: Equality theorem for operation value. (Contributed by NM, 28-Feb-1995)

Ref Expression
Assertion oveq F = G A F B = A G B

Proof

Step Hyp Ref Expression
1 fveq1 F = G F A B = G A B
2 df-ov A F B = F A B
3 df-ov A G B = G A B
4 1 2 3 3eqtr4g F = G A F B = A G B