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We call a tree $T$ is \emph{even} if every pair of its leaves is joined by a path of even length. Jackson and Yoshimoto~[J. Graph Theory, 2024] conjectured that every $r$-regular nonbipartite connected graph $G$ has a spanning even tree.…

Combinatorics · Mathematics 2024-09-11 Jiangdong Ai , Zhipeng Gao , Xiangzhou Liu , Jun Yue

We give a proof for sharp estimate for the number of spanning trees using linear algebra and generalize this bound to multigraphs. In addition, we show that this bound is tight for complete graphs. In addition, we give estimates for number…

Combinatorics · Mathematics 2022-12-01 K. V. Chelpanov

Measuring the complexity of tree structures can be beneficial in areas that use tree data structures for storage, communication, and processing purposes. This complexity can then be used to compress tree data structures to their…

Information Theory · Computer Science 2023-09-19 Amirmohammad Farzaneh , Mihai-Alin Badiu , Justin P. Coon

We apply a recent duality theorem for tangles in abstract separation systems to derive tangle-type duality theorems for width-parameters in graphs and matroids. We further derive a duality theorem for the existence of clusters in large data…

Combinatorics · Mathematics 2020-01-24 Reinhard Diestel , Sang-il Oum

Adjacency polytopes, a.k.a. symmetric edge polytopes, associated with undirected graphs have been defined and studied in several seemingly independent areas including number theory, discrete geometry, and dynamical systems. In particular,…

Combinatorics · Mathematics 2020-07-15 Tianran Chen , Evgeniia Korchevskaia

Transport through generalized trees is considered. Trees contain the simple nodes and supernodes, either well-structured regular subgraphs or those with many triangles. We observe a superdiffusion for the highly connected nodes while it is…

Disordered Systems and Neural Networks · Physics 2009-11-11 D. Volchenkov , Ph. Blanchard

We prove that every graph has a canonical tree of tree-decompositions that distinguishes all principal tangles (these include the ends and various kinds of large finite dense structures) efficiently. Here `trees of tree-decompositions' are…

Combinatorics · Mathematics 2020-04-08 Johannes Carmesin , Matthias Hamann , Babak Miraftab

Robertson and Seymour proved two fundamental theorems about tangles in graphs: the tree-of-tangles theorem, which says that every graph has a tree-decomposition such that distinguishable tangles live in different nodes of the tree, and the…

Combinatorics · Mathematics 2025-01-08 Sandra Albrechtsen

Here, we suggest a method to represent general directed uniform and non-uniform hypergraphs by different connectivity tensors. We show many results on spectral properties of undirected hypergraphs also hold for general directed uniform…

Spectral Theory · Mathematics 2018-08-16 Anirban Banerjee , Arnab Char

We present time-efficient distributed algorithms for decomposing graphs with large edge or vertex connectivity into multiple spanning or dominating trees, respectively. As their primary applications, these decompositions allow us to achieve…

Data Structures and Algorithms · Computer Science 2013-11-22 Keren Censor-Hillel , Mohsen Ghaffari , Fabian Kuhn

Trees fill many extremal roles in graph theory, being minimally connected and serving a critical role in the definition of $n$-good graphs. In this article, we consider the generalization of trees to the setting of $r$-uniform hypergraphs…

Combinatorics · Mathematics 2017-10-17 Mark Budden , Andrew Penland

One perspective on tree decompositions is that they display (low-order) separations of the underlying graph or matroid. The separations displayed by a tree decomposition are necessarily nested. In 2013, Clark and Whittle proved the…

Combinatorics · Mathematics 2023-12-22 Ann-Kathrin Elm , Hendrik Heine

We build on recent work of Yeats, Courtiel, and others involving connected chord diagrams. We first derive from a Hopf-algebraic foundation a class of tree-like functional equations and prove that they are solved by weighted generating…

Combinatorics · Mathematics 2021-04-07 Lukas Nabergall

We show that every graph admits a canonical tree-like decomposition into its $k$-edge-connected pieces for all $k\in\mathbb{N}\cup\{\infty\}$ simultaneously.

Combinatorics · Mathematics 2021-05-03 Christian Elbracht , Jan Kurkofka , Maximilian Teegen

Tangle structure trees, introduced in [3], offer a unified data structure that displays all the tangles of a graph or data set together with certificates for the non-existence of any other tangles, either locally or overall. In this paper…

Combinatorics · Mathematics 2026-03-19 Hanno von Bergen , Reinhard Diestel

Thomas proved that every undirected graph admits a linked tree decomposition of width equal to its treewidth. In this paper, we generalize Thomas's theorem to digraphs. We prove that every digraph G admits a linked directed path…

Combinatorics · Mathematics 2014-04-25 Shiva Kintali

We study generalized splines from the perspective of the representation theory of the category of graphs with contractions. Our main theorem proves a kind of finite generation, which in turn implies the existence of a ``universal generating…

Combinatorics · Mathematics 2026-05-26 Jacob Matherne , Eric Ramos , Julianna Tymoczko

This paper develops a structural theory of unique shortest paths in real-weighted graphs. Our main goal is to characterize exactly which sets of node sequences, which we call path systems, can be realized as unique shortest paths in a graph…

Data Structures and Algorithms · Computer Science 2018-10-18 Greg Bodwin

Recently, so-called treebased phylogenetic networks have gained considerable interest in the literature, where a treebased network is a network that can be constructed from a phylogenetic tree, called the base tree, by adding additional…

Populations and Evolution · Quantitative Biology 2019-11-28 Mareike Fischer , Michelle Galla , Lina Herbst , Yangjing Long , Kristina Wicke

In mathematics and computer science, connectivity is one of the basic concepts of matroid theory: it asks for the minimum number of elements which need to be removed to disconnect the remaining nodes from each other. It is closely related…

Artificial Intelligence · Computer Science 2013-11-06 Bin Yang , William Zhu
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