Weak subalgebra lattices of monounary partial algebras
Let be a finite lattice with a least element 0. is an annihilating-ideal graph of in which the vertex set is the set of all nontrivial ideals of , and two distinct vertices and are adjacent if and only if . We completely characterize all finite lattices whose line graph associated to an annihilating-ideal graph, denoted by , is a planar or projective graph.