Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Functions
isoeq1
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isoeq2
Metamath Proof Explorer
Ascii
Unicode
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