Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
The difference, union, and intersection of two classes
The intersection of two classes
ineq2
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ineq12
Metamath Proof Explorer
Ascii
Unicode
Theorem
ineq2
Description:
Equality theorem for intersection of two classes.
(Contributed by
NM
, 26-Dec-1993)
Ref
Expression
Assertion
ineq2
⊢
A
=
B
→
C
∩
A
=
C
∩
B
Proof
Step
Hyp
Ref
Expression
1
ineq1
⊢
A
=
B
→
A
∩
C
=
B
∩
C
2
incom
⊢
C
∩
A
=
A
∩
C
3
incom
⊢
C
∩
B
=
B
∩
C
4
1
2
3
3eqtr4g
⊢
A
=
B
→
C
∩
A
=
C
∩
B