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ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Classes
Class equality
neqcomd
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eqeq2d
Metamath Proof Explorer
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Unicode
Theorem
neqcomd
Description:
Commute an inequality.
(Contributed by
Rohan Ridenour
, 3-Aug-2023)
Ref
Expression
Hypothesis
neqcomd.1
⊢
φ
→
¬
A
=
B
Assertion
neqcomd
⊢
φ
→
¬
B
=
A
Proof
Step
Hyp
Ref
Expression
1
neqcomd.1
⊢
φ
→
¬
A
=
B
2
eqcom
⊢
A
=
B
↔
B
=
A
3
1
2
sylnib
⊢
φ
→
¬
B
=
A