<p>We prove that for every planar graph <i>X</i> of treedepth <i>h</i>, there exists a positive integer <i>c</i> such that for every <i>X</i>-minor-free graph <i>G</i>, there exists a graph <i>H</i> of treewidth at most <i>f</i>(<i>h</i>) such that <i>G</i> is isomorphic to a subgraph of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(H\boxtimes K_c\)</EquationSource> </InlineEquation>. This is a qualitative strengthening of the Grid-Minor Theorem of Robertson and Seymour&#xa0;(JCTB, 1986), and treedepth is the optimal parameter in such a result. We give three applications of this result: (1) improved upper bounds for the weak coloring numbers of graphs excluding a given minor, (2) an improved product structure theorem for apex-minor-free graphs, and (3) improved upper bounds for the <i>p</i>-centered chromatic number of graphs excluding a given minor.</p>

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The Grid-Minor Theorem Revisited

  • Vida Dujmović,
  • Robert Hickingbotham,
  • Jędrzej Hodor,
  • Gwenaël Joret,
  • Hoang La,
  • Piotr Micek,
  • Pat Morin,
  • Clément Rambaud,
  • David R. Wood

摘要

We prove that for every planar graph X of treedepth h, there exists a positive integer c such that for every X-minor-free graph G, there exists a graph H of treewidth at most f(h) such that G is isomorphic to a subgraph of \(H\boxtimes K_c\) . This is a qualitative strengthening of the Grid-Minor Theorem of Robertson and Seymour (JCTB, 1986), and treedepth is the optimal parameter in such a result. We give three applications of this result: (1) improved upper bounds for the weak coloring numbers of graphs excluding a given minor, (2) an improved product structure theorem for apex-minor-free graphs, and (3) improved upper bounds for the p-centered chromatic number of graphs excluding a given minor.