The Contraction Lemma

Grzegorz Bancerek

Warsaw University, Bialystok

Supported by RPBP.III-24.C1.

Summary.

The article includes the proof of the contraction lemma which claims that every class in which the axiom of extensionality is valid is isomorphic with a transitive class. In this article the isomorphism (wrt membership relation) of two sets is defined. It is based on [6].

MML Identifier: ZF_COLLA

Contents (PDF format)

Bibliography

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