Prime ideals in the lattice of additive induced-hereditary graph properties

An additive induced-hereditary property of graphs is any class of finite simple graphs which is closed under isomorphisms, disjoint unions and induced subgraphs. The set of all additive induced-hereditary properties of graphs, partially ordered by set inclusion, forms a completely distributive lattice. We introduce the notion of the join-decomposability number of a property and then we prove that the prime ideals of the lattice of all additive induced-hereditary properties are divided into two groups, determined either by a set of excluded joinirreducible properties or determined by a set of excluded properties with infinite join-decomposability number. We provide non-trivial examples of each type.