Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Unordered and ordered pairs
opeq12
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opeq1i
Metamath Proof Explorer
Ascii
Unicode
Theorem
opeq12
Description:
Equality theorem for ordered pairs.
(Contributed by
NM
, 28-May-1995)
Ref
Expression
Assertion
opeq12
⊢
A
=
C
∧
B
=
D
→
A
B
=
C
D
Proof
Step
Hyp
Ref
Expression
1
opeq1
⊢
A
=
C
→
A
B
=
C
B
2
opeq2
⊢
B
=
D
→
C
B
=
C
D
3
1
2
sylan9eq
⊢
A
=
C
∧
B
=
D
→
A
B
=
C
D