Abstract. A description is obtained of all pseudocomplemented semilattices $S$ for which the set of idempotent endomorphisms is closed under composition. Those $S$ for which the endomorphism monoid is orthodox are then identified.

AMS Subject Classification (1991): 06A12, 20M19; 08A35

Keyword(s): Endomorphism monoid, orthodox semigroup, regular semigroup, pseudocomplemented semilattice

Received September 4, 1995. (Registered under 5667/2009.)