Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Negated equality and membership
Negated equality
neqne
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neirr
Metamath Proof Explorer
Ascii
Unicode
Theorem
neqne
Description:
From non-equality to inequality.
(Contributed by
Glauco Siliprandi
, 11-Dec-2019)
Ref
Expression
Assertion
neqne
⊢
¬
A
=
B
→
A
≠
B
Proof
Step
Hyp
Ref
Expression
1
id
⊢
¬
A
=
B
→
¬
A
=
B
2
1
neqned
⊢
¬
A
=
B
→
A
≠
B