Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Subclasses and subsets, proper subclasses and subsets
Proper subclasses and subsets
wpss
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df-pss
Metamath Proof Explorer
Ascii
Structured
Syntax definition
wpss
Description:
Syntax for the proper subclass predicate.
Ref
Expression
Assertion
wpss
wff
𝐴
⊊
𝐵