Results 11 to 20 of about 1,862,441 (301)

Graph Minors. XXII. Irrelevant vertices in linkage problems

open access: yesJournal of Combinatorial Theory Series B, 2012
In the algorithm for the disjoint paths problem given in Graph Minors XIII, we used without proof a lemma that, in solving such a problem, a vertex which was sufficiently “insulated” from the rest of the graph by a large planar piece of the graph was ...
Paul Seymour
exaly   +3 more sources

Graph minors. X. Obstructions to tree-decomposition

open access: yesJournal of Combinatorial Theory Series B, 1991
Roughly, a graph has small “tree-width” if it can be constructed by piecing small graphs together in a tree structure. Here we study the obstructions to the existence of such a tree structure.
N. Robertson, P. Seymour
exaly   +3 more sources

Optimizing the Graph Minors Weak Structure Theorem [PDF]

open access: yesSIAM Journal on Discrete Mathematics, 2011
One of the major results of [N. Robertson and P. D. Seymour, Graph minors. XIII. The disjoint paths problem, J. Combin. Theory Ser. B, 63 (1995), pp. 65--110], also known as the weak structure theorem, reveals the local structure of graphs excluding some
Archontia C. Giannopoulou, D. Thilikos
semanticscholar   +2 more sources

The Behavior of Tree-Width and Path-Width Under Graph Operations and Graph Transformations

open access: yesAlgorithms
Tree-width and path-width are well-known graph parameters. Many NP-hard graph problems admit polynomial-time solutions when restricted to graphs of bounded tree-width or bounded path-width. In this work, we study the behavior of tree-width and path-width
Frank Gurski, Robin Weishaupt
doaj   +2 more sources

On cut polytopes and graph minors [PDF]

open access: yesDiscrete Optimization, 2023
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Konstantinos Kaparis   +2 more
openaire   +4 more sources

Graph Minors. XX. Wagner's conjecture

open access: yesJournal of Combinatorial Theory Series B, 2004
N. Robertson, P. Seymour
exaly   +2 more sources

Shallow Minors, Graph Products, and Beyond-Planar Graphs [PDF]

open access: yesSIAM Journal on Discrete Mathematics, 2021
The planar graph product structure theorem of Dujmovi\'{c}, Joret, Micek, Morin, Ueckerdt, and Wood [J. ACM 2020] states that every planar graph is a subgraph of the strong product of a graph with bounded treewidth and a path.
Robert Hickingbotham, D. Wood
semanticscholar   +1 more source

Arrangements Of Minors In The Positive Grassmannian And a Triangulation of The Hypersimplex [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2015
The structure of zero and nonzero minors in the Grassmannian leads to rich combinatorics of matroids. In this paper, we investigate an even richer structure of possible equalities and inequalities between the minors in the positive Grassmannian.
Miriam Farber, Yelena Mandelshtam
doaj   +1 more source

The sandpile group of a thick cycle graph

open access: yesElectronic Journal of Graph Theory and Applications, 2022
The majority of graphs whose sandpile groups are known are either regular or simple. We give an explicit formula for a family of non-regular multi-graphs called thick cycles. A thick cycle graph is a cycle where multi-edges are permitted.
Diane Christine Alar   +4 more
doaj   +1 more source

Minor-Universal Graph for Graphs on Surfaces

open access: yesCoRR, 2023
We show that, for every n and every surface $Σ$, there is a graph U embeddable on $Σ$ with at most cn^2 vertices that contains as minor every graph embeddable on $Σ$ with n vertices. The constant c depends polynomially on the Euler genus of $Σ$. This generalizes a well-known result for planar graphs due to Robertson, Seymour, and Thomas [Quickly ...
Cyril Gavoille, Claire Hilaire
openaire   +2 more sources

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