From polynomial time queries to graph structure theory

  • Authors:
  • Martin Grohe

  • Affiliations:
  • Humboldt-Universität Berlin, Germany

  • Venue:
  • Communications of the ACM
  • Year:
  • 2011

Quantified Score

Hi-index 48.22

Visualization

Abstract

We give a logical characterization of the polynomial-time properties of graphs with excluded minors: For every class C of graphs such that some graph H is not a minor of any graph in C, a property P of graphs in C is decidable in polynomial time if and only if it is definable in fixed-point logic with counting. Furthermore, we prove that for every class C of graphs with excluded minors there is a k such that a simple combinatorial algorithm, namely "the k-dimensional Weisfeiler--Lehman algorithm," decides isomorphism of graphs in C in polynomial time.