Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Functions
isoeq2
Next ⟩
isoeq3
Metamath Proof Explorer
Ascii
Unicode
Theorem
isoeq2
Description:
Equality theorem for isomorphisms.
(Contributed by
NM
, 17-May-2004)
Ref
Expression
Assertion
isoeq2
⊢
R
=
T
→
H
Isom
R
,
S
A
B
↔
H
Isom
T
,
S
A
B
Proof
Step
Hyp
Ref
Expression
1
breq
⊢
R
=
T
→
x
R
y
↔
x
T
y
2
1
bibi1d
⊢
R
=
T
→
x
R
y
↔
H
⁡
x
S
H
⁡
y
↔
x
T
y
↔
H
⁡
x
S
H
⁡
y
3
2
2ralbidv
⊢
R
=
T
→
∀
x
∈
A
∀
y
∈
A
x
R
y
↔
H
⁡
x
S
H
⁡
y
↔
∀
x
∈
A
∀
y
∈
A
x
T
y
↔
H
⁡
x
S
H
⁡
y
4
3
anbi2d
⊢
R
=
T
→
H
:
A
⟶
1-1 onto
B
∧
∀
x
∈
A
∀
y
∈
A
x
R
y
↔
H
⁡
x
S
H
⁡
y
↔
H
:
A
⟶
1-1 onto
B
∧
∀
x
∈
A
∀
y
∈
A
x
T
y
↔
H
⁡
x
S
H
⁡
y
5
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
6
df-isom
⊢
H
Isom
T
,
S
A
B
↔
H
:
A
⟶
1-1 onto
B
∧
∀
x
∈
A
∀
y
∈
A
x
T
y
↔
H
⁡
x
S
H
⁡
y
7
4
5
6
3bitr4g
⊢
R
=
T
→
H
Isom
R
,
S
A
B
↔
H
Isom
T
,
S
A
B