-systems of unary algebras. I: On maximal and greatest -classes of the direct product of unary algebras
-systems of unary algebras. II: Maximal and minimal subalgebras of the direct products of unary algebras
Remark on partially ordered sets, universal algebras and semigroups
Representation of connected monounary algebras by means of irreducibles
The aim of the present paper is to describe all connected monounary algebras for which there exists a representation by means of connected monounary algebras which are retract irreducible in the class (or in ).
Representation of ordered classes by classes of connected unary algebras
Retract irreducibility of connected monounary algebras. I
Retract irreducibility of connected monounary algebras. II
Retract irreducibility of monounary algebras
Retract varieties of monounary algebras
Retracts of monounary algebras corresponding to groupoids