Representing Congruence Lattices of Lattices with Partial Unary Operations as Congruence Lattices of Lattices. I. Interval Equivalence

Let L be a bounded lattice, let [a, b] and [c, d] be intervals of L, and let φ : [a, b] → [c, d] be an isomorphism between these two intervals. Let us consider the algebra L↔ φ = 〈L;∧,∨, φ, φ−1〉, which is a lattice with two partial unary operations. We construct a bounded lattice K (in fact, a convex extension of L) such that the congruence lattice of L↔ φ is isomorphic to the congruence lattice of K, and extend this result to (many) families of isomorphisms. This result presents a lattice K whose congruence lattice is derived from the congruence lattice of L in a novel way.