“…Despite providing one of the most natural generalizations of -groups, the structure theory of distributive -monoids is not yet at a very sophisticated state, possibly because the tools and techniques of -group theory do not extend well in the absence of inverses. In particular, there does not yet exist a good characterization of congruences of distributive -monoids (but see [30,4,9], where congruences are constructed from prime lattice ideals of distributive -monoids) and not much is known about subdirectly irreducible members of this class to date (see [38], covering the finite commutative case). On the other hand, there exists a natural analogue of the representation theorem of Holland [24] of -groups as subalgebras of automorphism -groups of chains.…”