STABLE BINARY RELATIONS ON UNIVERSAL ALGEBRAS
G I Žitomirskiĭ · Mathematics of the USSR-Sbornik · 1970
With every universal algebra there is associated the ordered involutory semigroup of all its correspondences (stable binary relations). Two universal algebras are said to be R-isomorphic if their semigroups of correspondences are isomorphic. A subclass K of the class C of universal algebras is R-characterizable in C if it is closed with respect to R-isomorphisms. In this article we single out a number of R-characterizable classes of universal algebras. It is shown that the complete preimage of an R-characterizable class is R-characterizable. The results obtained are applied to classes of semigroups and semiheaps. Bibliography: 6 items.