Metamath Proof Explorer


Theorem imaeq2d

Description: Equality theorem for image. (Contributed by FL, 15-Dec-2006)

Ref Expression
Hypothesis imaeq1d.1 φA=B
Assertion imaeq2d φCA=CB

Proof

Step Hyp Ref Expression
1 imaeq1d.1 φA=B
2 imaeq2 A=BCA=CB
3 1 2 syl φCA=CB