:: Built-in Concepts :: by Andrzej Trybulec :: :: Received January 1, 1989 :: Copyright (c) 1990-2021 Association of Mizar Users

:: This article documents a part of the Mizar axiomatics - it shows how
:: the primitives of set theory are introduced in the Mizar Mathematical
:: Library.
:: Please note that the notions defined here are not subject to standard
:: verification, so the Mizar verifier and other utilities may report
:: errors when processing this article.

:: the primitives of set theory are introduced in the Mizar Mathematical

:: Library.

:: Please note that the notions defined here are not subject to standard

:: verification, so the Mizar verifier and other utilities may report

:: errors when processing this article.