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We show how the theory of tangles is equivalent to that of well-connected tangles. These are drawn on a surface with boundary, and equivalent via Reidemeister moves of a restricted kind. This reworking of the graphical foundations for link…

Geometric Topology · Mathematics 2013-02-19 Peter M. Johnson , Sóstenes Lins

Starting from the working hypothesis that both physics and the corresponding mathematics have to be described by means of discrete concepts on the Planck-scale, one of the many problems one has to face in this enterprise is to find the…

High Energy Physics - Theory · Physics 2010-05-12 Thomas Nowotny , Manfred Requardt

Packing graphs is a combinatorial problem where several given graphs are being mapped into a common host graph such that every edge is used at most once. In the planar tree packing problem we are given two trees T1 and T2 on n vertices and…

Computational Geometry · Computer Science 2016-03-28 Markus Geyer , Michael Hoffmann , Michael Kaufmann , Vincent Kusters , Csaba D. Tóth

We extend Robertson and Seymour's tangle-tree duality theorem to infinite graphs.

Combinatorics · Mathematics 2026-03-13 Sandra Albrechtsen

A thesaurus is one, out of many, possible representations of term (or word) connectivity. The terms of a thesaurus are seen as the nodes and their relationship as the links of a directed graph. The directionality of the links retains all…

A tree-based dictionary learning model is developed for joint analysis of imagery and associated text. The dictionary learning may be applied directly to the imagery from patches, or to general feature vectors extracted from patches or…

Machine Learning · Computer Science 2012-10-19 Lingbo Li , XianXing Zhang , Mingyuan Zhou , Lawrence Carin

A tanglegram consists of two rooted binary trees with the same number of leaves and a perfect matching between the leaves of the trees. Given a size-$n$ tanglegram, i.e., a tanglegram for two trees with $n$ leaves, a multiset of induced…

Combinatorics · Mathematics 2025-08-18 Ann Clifton , Eva Czabarka , Kevin Liu , Sarah Loeb , Utku Okur , Laszlo Szekely , Kristina Wicke

A painting consists of objects which are arranged in specific ways. The art of painting is drawing the objects, which can be considered as known trends, in an expressive manner. Detrended methods are suitable for characterizing the artistic…

Data Analysis, Statistics and Probability · Physics 2010-11-30 P. Pedram , G. R. Jafari

We prove a tangle-tree theorem and a tangle duality theorem for abstract separation systems $\vec S$ that are submodular in the structural sense that, for every pair of oriented separations, $\vec S$ contains either their meet or their join…

Combinatorics · Mathematics 2019-04-25 Reinhard Diestel , Joshua Erde , Daniel Weißauer

Tangle is a concept in graph theory that has a dual relationship with branch-width which is well-known graph width parameter. Ultrafilter, a fundamental notion in mathematics, is similarly known to have a dual relationship with branch-width…

Combinatorics · Mathematics 2026-03-03 Takaaki Fujita

A graph is $\alpha$-excellent if every vertex of the graph is contained in some maximum independent set of the graph. In this paper, we present two characterizations of the $\alpha$-excellent $2$-trees.

Combinatorics · Mathematics 2022-10-27 Magda Dettlaff , Michael A. Henning , Jerzy Topp

The Pathwidth Theorem states that if a class of graphs has unbounded pathwidth, then it contains all trees as graph minors. We prove a similar result for dense graphs. More precisely, we give a finite family of tree-like patterns and prove…

Logic in Computer Science · Computer Science 2026-04-09 Mikołaj Bojańczyk , Pierre Ohlmann

In this note we gather the theoretical outlines of three basic algorithms for tangles in abstract separation systems: a naive tree search for finding tangles; an algorithm which outputs a certificate for the non-existence of tangles if…

Combinatorics · Mathematics 2025-05-16 Christian Elbracht , Jay Lilian Kneip , Maximilian Teegen

We prove a general duality theorem for tangle-like dense objects in combinatorial structures such as graphs and matroids. This paper continues, and assumes familiarity with, the theory developed in [6]

Combinatorics · Mathematics 2014-06-17 Reinhard Diestel , Sang-il Oum

Abstract separation systems provide a simple general framework in which both tree-shape and high cohesion of many combinatorial structures can be expressed, and their duality proved. Applications range from tangle-type duality and tree…

Combinatorics · Mathematics 2017-04-19 Reinhard Diestel

We propose a method for characterizing large complex networks by introducing a new matrix structure, unique for a given network, which encodes structural information; provides useful visualization, even for very large networks; and allows…

Disordered Systems and Neural Networks · Physics 2008-02-28 J. P. Bagrow , E. M. Bollt , J. D. Skufca , D. ben-Avraham

This is a new and short proof of the main theorem of classical structure tree theory. Namely, we show the existence of certain automorphism-invariant tree-decompositions of graphs based on the principle of removing finitely many edges. This…

Group Theory · Mathematics 2010-03-05 Bernhard Krön

A graph has tree-width at most $k$ if it can be obtained from a set of graphs each with at most $k+1$ vertices by a sequence of clique sums. We refine this definition by, for each non-negative integer $\theta$, defining the…

Combinatorics · Mathematics 2016-09-30 Jim Geelen , Benson Joeris

The Ramsey's theorem says that a graph with sufficiently many vertices contains a clique or stable set with many vertices. Now we attach some parameter to every vertex, such as degree. Consider the case a graph with sufficiently many…

Combinatorics · Mathematics 2023-07-18 Jin Sun

Bases, mappings, projections and metrics, natural for Neural network training, are introduced. Graph-theoretical interpretation is offered. Non-Gaussianity naturally emerges, even in relatively simple datasets. Training statistics,…

Computer Vision and Pattern Recognition · Computer Science 2018-09-19 Galin Georgiev