Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Negated equality and membership
Negated membership
wnel
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df-nel
Metamath Proof Explorer
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Syntax definition
wnel
Description:
Extend wff notation to include negated membership.
Ref
Expression
Assertion
wnel
wff
A
∉
B