:: Birkhoff Theorem for Many Sorted Algebras
:: by Artur Korni{\l}owicz
::
:: Received June 19, 1997
:: Copyright (c) 1997 Association of Mizar Users
:: BIRKHOFF semantic presentation
:: deftheorem Def1 defines -hash BIRKHOFF:def 1 :
theorem Th1: :: BIRKHOFF:1