Flip of lattices

TL;DR

This paper introduces a new combinatorial operation called a flip on posets, studies its properties, and explores its implications for lattice theory, including the concept of mutations and new classes of lattices.

Contribution

It defines and characterizes mutations as flips that preserve lattice structure, introduces mutable lattices, and constructs a new class called Ordovician lattices.

Findings

Mutations are characterized by a necessary and sufficient condition.

Mutable lattices are proven to be semidistributive.

Type-A and type-B Cambrian lattices are locally mutable and related by mutations.

Abstract

In this paper, we introduce a new combinatorial operation, called a flip, on arbitrary partially ordered sets. We define a mutation to be a flip that maps a lattice to a lattice. We study properties of flips, and give a necessary and sufficient condition for a flip to be a mutation. We introduce locally mutable lattices and mutable lattices in terms of flips, and prove that mutable lattices are semidistributive. We show that type-A and type-B Cambrian lattices are locally mutable, and those associated with the finite-type Coxeter quivers with different orientations are related also by the sequence of mutations. Finally we introduce a new class of lattices, called Ordovician lattices, as the lattices obtained from Cambrian lattices by iterated mutations. We provide conjectures on the structure of Ordovician lattices and on the compatibility between our mutation and the mutation in the theory of cluster algebras.