Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Relations
elvv
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elvvv
Metamath Proof Explorer
Ascii
Unicode
Theorem
elvv
Description:
Membership in universal class of ordered pairs.
(Contributed by
NM
, 4-Jul-1994)
Ref
Expression
Assertion
elvv
⊢
A
∈
V
×
V
↔
∃
x
∃
y
A
=
x
y
Proof
Step
Hyp
Ref
Expression
1
elxp
⊢
A
∈
V
×
V
↔
∃
x
∃
y
A
=
x
y
∧
x
∈
V
∧
y
∈
V
2
vex
⊢
x
∈
V
3
vex
⊢
y
∈
V
4
2
3
pm3.2i
⊢
x
∈
V
∧
y
∈
V
5
4
biantru
⊢
A
=
x
y
↔
A
=
x
y
∧
x
∈
V
∧
y
∈
V
6
5
2exbii
⊢
∃
x
∃
y
A
=
x
y
↔
∃
x
∃
y
A
=
x
y
∧
x
∈
V
∧
y
∈
V
7
1
6
bitr4i
⊢
A
∈
V
×
V
↔
∃
x
∃
y
A
=
x
y