This paper provides an abstract characterization of the inverse monoids that appear as monoids of bi-congruences of finite minimal algebras generating arithmetical varieties. As a tool, a matrixâ€¦ (More)

An algebra is called weakly diagonal if every subuniverse of its square contains the graph of an automorphism. We show that every variety generated by a finite algebra with no proper subalgebras hasâ€¦ (More)

On supported algebras Janis Cirulis University of Latvia Given a (countable) set of variables Var, we call a supported algebra a pair (A, spp), where A is an algebra and spp is a relation betweenâ€¦ (More)