On monophonic position sets in graphs

• Published in: Discrete Applied Mathematics Vol. 354; pp. 72 - 82
• Main Authors: Thomas, Elias John, Chandran S.V., Ullas, Tuite, James, Di Stefano, Gabriele
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2024
• Subjects: General position number; General position set; Monophonic position number; Monophonic position set; Monophonic position number; General position number; Monophonic position set; General position set
• ISSN: 0166-218X; 1872-6771
• DOI: 10.1016/j.dam.2023.02.021

The general position problem in graph theory asks for the largest set S of vertices of a graph G such that no shortest path of G contains more than two vertices of S. In this paper we consider a variant of the general position problem called the monophonic position problem, obtained by replacing ‘shortest path’ by ‘induced path’. We prove some basic properties and bounds for the monophonic position number of a graph and determine the monophonic position number of some graph families, including unicyclic graphs, complements of bipartite graphs and split graphs. We show that the monophonic position number of triangle-free graphs is bounded above by the independence number. We present realisation results for the general position number, monophonic position number and monophonic hull number. Finally we discuss the complexity of the monophonic position problem.