Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Negated equality and membership
Negated equality
neir
Next ⟩
nne
Metamath Proof Explorer
Ascii
Structured
Theorem
neir
Description:
Inference associated with
df-ne
.
(Contributed by
BJ
, 7-Jul-2018)
Ref
Expression
Hypothesis
neir.1
⊢
¬
𝐴
=
𝐵
Assertion
neir
⊢
𝐴
≠
𝐵
Proof
Step
Hyp
Ref
Expression
1
neir.1
⊢
¬
𝐴
=
𝐵
2
df-ne
⊢
(
𝐴
≠
𝐵
↔ ¬
𝐴
=
𝐵
)
3
1
2
mpbir
⊢
𝐴
≠
𝐵