Metamath Proof Explorer


Theorem fovcld

Description: Closure law for an operation. (Contributed by NM, 19-Apr-2007) (Revised by Thierry Arnoux, 17-Feb-2017)

Ref Expression
Hypothesis fovcld.1 φ F : R × S C
Assertion fovcld φ A R B S A F B C

Proof

Step Hyp Ref Expression
1 fovcld.1 φ F : R × S C
2 3simpc φ A R B S A R B S
3 ffnov F : R × S C F Fn R × S x R y S x F y C
4 3 simprbi F : R × S C x R y S x F y C
5 1 4 syl φ x R y S x F y C
6 5 3ad2ant1 φ A R B S x R y S x F y C
7 oveq1 x = A x F y = A F y
8 7 eleq1d x = A x F y C A F y C
9 oveq2 y = B A F y = A F B
10 9 eleq1d y = B A F y C A F B C
11 8 10 rspc2v A R B S x R y S x F y C A F B C
12 2 6 11 sylc φ A R B S A F B C