Clique transversal size problem proved hard for complex graphs

W[1]-Hardness of Upper Clique Transversal

Computational ComplexityDiscrete MathematicsData Structures and Algorithms

Summary

This paper looks at a puzzle about graphs, which are like networks of dots and lines. The puzzle is about finding a special group of dots that touches every big tightly connected group called cliques. The authors show that figuring out if such a group can be big is very hard in a technical sense, meaning no fast shortcuts are likely to exist. This helps us understand the limits of solving these kinds of network problems.

What this means in practice

  • For graph algorithm designers: Avoid seeking efficient solutions for large minimal clique transversals given size constraints due to proven computational hardness.
  • For complex networks analysts: Recognize that finding large minimal vertex sets touching maximal cliques is computationally intractable, guiding approach choices.

A theory result. No direct application yet.

Authors

Pascal J. Gollin, Tesshu Hanaka, Ekkehard Köhler, Martin Milanič, Yushi Uno

Abstract

A clique transversal of a graph is a set of vertices intersecting every maximal clique. We prove that deciding whether a graph has an inclusion-wise minimal clique transversal of size at least $k$ is W[1]-hard when parameterized by $k$.