Linear-semiorders and their incomparability graphs

TL;DR

This paper introduces linear-semiorders, a new subclass of partial orders formed by intersecting linear orders with semiorders, and provides polynomial-time recognition algorithms for these structures and their incomparability graphs.

Contribution

It defines linear-semiorders, characterizes them, and develops polynomial-time algorithms for recognizing these orders and their incomparability graphs.

Findings

Linear-semiorders are characterized by a new structural property.

Recognition algorithms for linear-semiorders run in polynomial time.

Incomparability graphs of linear-semiorders can be efficiently recognized.

Abstract

A linear-interval order is the intersection of a linear order and an interval order. For this class of orders, several structural results have been known. This paper introduces a new subclass of linear-interval orders. We call a partial order a \emph{linear-semiorder} if it is the intersection of a linear order and a semiorder. We show a characterization and a polynomial-time recognition algorithm for linear-semiorders. We also prove that being a linear-semiorder is a comparability invariant, showing that incomparability graphs of linear-semiorders can be recognized in polynomial time.