Deciding absorption in relational structures

Abstract

We prove that for finite, finitely related algebras, the concepts of an absorbing subuniverse and a JA ' onsson absorbing subuniverse coincide. Consequently, it is decidable whether a given subset is an absorbing subuniverse of the polymorphism algebra of a given relational structure.

Keywords

• finitely related algebra
• absorbing subalgebra
• Jonsson absorbing subalgebra
• near unanimity
• congruence distributivity