Metamath Proof Explorer


Theorem reseq2d

Description: Equality deduction for restrictions. (Contributed by Paul Chapman, 22-Jun-2011)

Ref Expression
Hypothesis reseqd.1 φA=B
Assertion reseq2d φCA=CB

Proof

Step Hyp Ref Expression
1 reseqd.1 φA=B
2 reseq2 A=BCA=CB
3 1 2 syl φCA=CB