Abstract

A permutation graph can be defined as an intersection graph of segments whose endpoints lie on two parallel lines ell _1 and ell _2, one on each. A bipartite permutation graph is a permutation graph which is bipartite. In this paper we study the parameterized complexity of the bipartite permutation vertex deletion problem, which asks, for a given n-vertex graph, whether we can remove at most k vertices to obtain a bipartite permutation graph. This problem is mathsf {NP}-complete by the classical result of Lewis and Yannakakis [20]. We analyze the structure of the so-called almost bipartite permutation graphs which may contain holes (large induced cycles) in contrast to bipartite permutation graphs. We exploit the structural properties of the shortest hole in a such graph. We use it to obtain an algorithm for the bipartite permutation vertex deletion problem with running time {mathcal {O}}(9^k cdot n^9), and also give a polynomial-time 9-approximation algorithm.

Highlights

  • Many standard computational problems, including maximum clique, maximum independent set, or minimum coloring, which are NP-hard in general, have polynomial-time exact or approximation algorithms in restricted classes of graphs

  • In this paper we investigate for the first time the modification problems in graph classes related to partial orders

  • Our main result says that the bipartite permutation vertex deletion problem is fixed parameter tractable

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Summary

Introduction

Many standard computational problems, including maximum clique, maximum independent set, or minimum coloring, which are NP-hard in general, have polynomial-time exact or approximation algorithms in restricted classes of graphs. A linear order (W ,

Almost Bipartite Permutation Graphs
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