Definition of positively closed classes by endomorphism semigroups
Sergey Seraphimovich Marchenkov · Discrete Mathematics and Applications · 2012
The positively closed classes of multivalued logic are characterised with the use of endomorphism semigroups. All subsemigroups of the symmetric semigroup of degree k are described which are semigroups of endomorphisms of positively closed classes in P k . On the base of the obtained results, we find all positively precomplete classes in P k .