The Homomorphism Lattice Induced by a Finite Algebra

Abstract

Each finite algebra A induces a lattice L A via the quasi-order → on the finite members of the variety generated by A, where B →C if there exists a homomorphism from B to C. In this paper, we introduce the question: ‘Which lattices arise as the homomorphism lattice L A induced by a finite algebra A?’ Our main result is that each finite distributive lattice arises as L Q , for some quasi-primal algebra Q. We also obtain representations of some other classes of lattices as homomorphism lattices, including all finite partition lattices, all finite subspace lattices and all lattices of the form L ⊕1, where L is an interval in the subgroup lattice of a finite group.