Metamath Proof Explorer


Theorem isoeq1

Description: Equality theorem for isomorphisms. (Contributed by NM, 17-May-2004)

Ref Expression
Assertion isoeq1 H = G H Isom R , S A B G Isom R , S A B

Proof

Step Hyp Ref Expression
1 f1oeq1 H = G H : A 1-1 onto B G : A 1-1 onto B
2 fveq1 H = G H x = G x
3 fveq1 H = G H y = G y
4 2 3 breq12d H = G H x S H y G x S G y
5 4 bibi2d H = G x R y H x S H y x R y G x S G y
6 5 2ralbidv H = G x A y A x R y H x S H y x A y A x R y G x S G y
7 1 6 anbi12d H = G H : A 1-1 onto B x A y A x R y H x S H y G : A 1-1 onto B x A y A x R y G x S G y
8 df-isom H Isom R , S A B H : A 1-1 onto B x A y A x R y H x S H y
9 df-isom G Isom R , S A B G : A 1-1 onto B x A y A x R y G x S G y
10 7 8 9 3bitr4g H = G H Isom R , S A B G Isom R , S A B