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We give a short, topological proof that all graphs admit tree-decompositions displaying their topological ends.

Combinatorics · Mathematics 2021-12-03 Max Pitz

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

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

Much information about a graph can be obtained by studying its spanning trees. On the other hand, a graph can be regarded as a 1-dimensional cell complex, raising the question of developing a theory of trees in higher dimension. As observed…

Combinatorics · Mathematics 2015-06-24 Art M. Duval , Caroline J. Klivans , Jeremy L. Martin

In this paper we show that given a max-plus automaton (over trees, and with real weights) computing a function $f$ and a min-plus automaton (similar) computing a function $g$ such that $f\leqslant g$, there exists effectively an unambiguous…

Formal Languages and Automata Theory · Computer Science 2019-10-08 Thomas Colcombet , Sylvain Lombardy

We generalize several recognizability theorems for free single-sorted algebras to the field of many-sorted algebras and provide, in a uniform way and without using neither regular tree grammars nor tree automata, purely algebraic proofs of…

Formal Languages and Automata Theory · Computer Science 2024-01-18 Juan Climent Vidal , Enric Cosme Llópez

In this paper it is shown that for any network there is a uniquely determined network based on a structure tree that provides a convenient way of determining a minimal cut separating a pair $s, t$ where each of $s, t$ is either a vertex or…

Combinatorics · Mathematics 2015-01-05 M. J. Dunwoody

We study tree-to-tree transformations that can be defined in first-order logic or monadic second-order logic. We prove a decomposition theorem, which shows that every transformation can be obtained from prime transformations, such as…

Formal Languages and Automata Theory · Computer Science 2023-01-31 Mikołaj Bojańczyk , Amina Doumane

We give a common matroidal generalisation of `A Cantor-Bernstein theorem for paths in graphs' by Diestel and Thomassen and `A Cantor-Bernstein-type theorem for spanning trees in infinite graphs' by ourselves.

Combinatorics · Mathematics 2022-05-10 Attila Joó

This note contributes to the structure theory of abstract rigidity matroids in general dimension. In the spirit of classical matroid theory, we prove several cryptomorphic characterizations of abstract rigidity matroids (in terms of…

Combinatorics · Mathematics 2015-03-13 Emanuele Delucchi , Tim Lindemann

We exhibit an identity of abstract simplicial complexes between the well-studied complex of trees and the reduced minimal nested set complex of the partition lattice. We conclude that the order complex of the partition lattice can be…

Combinatorics · Mathematics 2007-05-23 Eva Maria Feichtner

In this work we provide a decomposition theorem for the class of quaternary and non-binary signed-graphic matroids. This generalizes previous results for binary signed-graphic matroids and graphic matroids, and it provides the theoretical…

Combinatorics · Mathematics 2015-10-26 Leonidas Pitsoulis , Eleni-Maria Vretta

In this series, we introduce and investigate the concept of connectoids, which captures the connectivity structure of various discrete objects such as undirected graphs, directed graphs, bidirected graphs, hypergraphs and finitary matroids.…

Combinatorics · Mathematics 2026-05-21 Nathan Bowler , Florian Reich

This is a survey article on trees, with a modest number of proofs to give a flavor of the way these topologies can be efficiently handled. Trees are defined in set-theorist fashion as partially ordered sets in which the elements below each…

General Topology · Mathematics 2007-05-23 Peter J. Nyikos

The tree share structure proposed by Dockins et al. is an elegant model for tracking disjoint ownership in concurrent separation logic, but decision procedures for tree shares are hard to implement due to a lack of a systematic theoretical…

Logic in Computer Science · Computer Science 2020-10-19 Xuan-Bach Le , Aquinas Hobor , Anthony W. Lin

We prove that every oriented tree on $n$ vertices with bounded maximum degree appears as a spanning subdigraph of every directed graph on $n$ vertices with minimum semidegree at least $n/2+o(n)$. This can be seen as a directed graph…

Combinatorics · Mathematics 2026-05-20 Richard Mycroft , Tássio Naia

We introduce some new symmetric tensor categories based on the combinatorics of trees: a discrete family $\mathcal{D}(n)$, for $n \ge 3$ an integer, and a continuous family $\mathcal{C}(t)$, for $t \ne 1$ a complex number. The construction…

Representation Theory · Mathematics 2024-03-19 Nate Harman , Ilia Nekrasov , Andrew Snowden

This paper gives two new combinatorial topological proofs of the classification of rational tangles. Each proof rests on an elegant lemma showing that rational tangles are isotopic to canonical alternating rational tangles. The first proof…

Geometric Topology · Mathematics 2009-09-29 Louis H. Kauffman , Sofia Lambropoulou

In this paper, we introduce two families of planar and self-similar graphs which have small-world properties. The constructed models are based on an iterative process where each step of a certain formulation of modules results in a final…

Combinatorics · Mathematics 2024-04-19 Muhammed Alaa Morsy , Mohamed Anwar , Abdallah Aboutahoun

We establish several extensions of the well-known Garden of Eden theorem for non-uniform cellular automata over the full shifts and over amenable group universes. In particular, our results describe quantitatively the relations between the…

Dynamical Systems · Mathematics 2023-04-04 Xuan Kien Phung