Metamath Proof Explorer


Theorem fveq2d

Description: Equality deduction for function value. (Contributed by NM, 29-May-1999)

Ref Expression
Hypothesis fveq2d.1 φA=B
Assertion fveq2d φFA=FB

Proof

Step Hyp Ref Expression
1 fveq2d.1 φA=B
2 fveq2 A=BFA=FB
3 1 2 syl φFA=FB