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We define a special case of tree decompositions for planar graphs that respect a given embedding of the graph. We study the analogous width of the resulting decomposition we call the embedded-width of a plane graph. We show both upper…

Discrete Mathematics · Computer Science 2017-03-23 Glencora Borradaile , Jeff Erickson , Hung Le , Robbie Weber

In this paper, we investigate the computational complexity of subgraph reconfiguration problems in directed graphs. More specifically, we focus on the problem of reconfiguring arborescences in a digraph, where an arborescence is a directed…

Data Structures and Algorithms · Computer Science 2023-03-16 Takehiro Ito , Yuni Iwamasa , Yasuaki Kobayashi , Yu Nakahata , Yota Otachi , Kunihiro Wasa

Graph pebbling is a network model for transporting discrete resources that are consumed in transit. Deciding whether a given configuration on a particular graph can reach a specified target is ${\sf NP}$-complete, even for diameter two…

Combinatorics · Mathematics 2017-01-17 Liliana Alcón , Marisa Gutierrez , Glenn Hurlbert

The number of spanning trees of a graph is an important invariant related to topological and dynamic properties of the graph, such as its reliability, communication aspects, synchronization, and so on. However, the practical enumeration of…

Discrete Mathematics · Computer Science 2016-04-05 Zhongzhi Zhang , Shunqi Wu , Mingyun Li , Francesc Comellas

Treewidth is a well-known graph invariant with multiple interesting applications in combinatorics. On the practical side, many NP-complete problems are polynomial-time (sometimes even linear-time) solvable on graphs of bounded treewidth. On…

Category Theory · Mathematics 2021-05-13 Zoltan A. Kocsis , Benjamin Merlin Bumpus

In this paper algebraic and combinatorial properties and a computation of the number of the spanning trees are developed for certain graphs. To this purpose, an original method, independent of the spectrum of the Laplacian matrix associated…

Combinatorics · Mathematics 2024-04-01 Maurizio Imbesi , Monica La Barbiera , Santo Saraceno

We consider the probability that a spanning tree chosen uniformly at random from a graph can be partitioned into a fixed number $k$ of trees of equal size by removing $k-1$ edges. In that case, the spanning tree is called {\em splittable}.…

Data Structures and Algorithms · Computer Science 2026-02-25 David Gillman , Jacob Platnick , Dana Randall

We prove that, among rectangular grid graphs with a fixed number of vertices, the number of spanning trees increases when the side lengths are made more balanced. In particular, among all rectangular grid graphs with $n^2$ vertices, the…

Combinatorics · Mathematics 2026-05-25 Jiechen Zhang

We present an explicit connected spanning structure that appears in a random graph just above the connectivity threshold with high probability.

Combinatorics · Mathematics 2021-11-29 Yahav Alon , Michael Krivelevich , Peleg Michaeli

Treewidth is a graph parameter of fundamental importance to algorithmic and structural graph theory. This paper surveys several graph parameters tied to treewidth, including separation number, tangle number, well-linked number and Cartesian…

Combinatorics · Mathematics 2016-01-29 Daniel J. Harvey , David R. Wood

Let $k\ge 2$ be an integer and $T_1,\ldots, T_k$ be spanning trees of a graph $G$. If for any pair of vertices $(u,v)$ of $V(G)$, the paths from $u$ to $v$ in each $T_i$, $1\le i\le k$, do not contain common edges and common vertices,…

Discrete Mathematics · Computer Science 2014-09-23 Benoit Darties , Nicolas Gastineau , Olivier Togni

The number of spanning trees of a graph $G$, denoted $\tau(G)$, is a well studied graph parameter with numerous connections to other areas of mathematics. In a recent remarkable paper, answering a question of Sedl\'a\v{c}ek from 1969, Chan,…

Combinatorics · Mathematics 2025-08-26 Noga Alon , Matija Bucić , Lior Gishboliner

A tree with at most k leaves is called k-ended tree, and a tree with exactly k leaves is called k-end tree, where a leaf is a vertex of degree one. Contraction of a graph G along the edge e means deleting the edge e and identifying its end…

Combinatorics · Mathematics 2016-12-30 Hamed Ghasemian Zoeram

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

Given a set of points in the plane, we want to establish a connection network between these points that consists of several disjoint layers. Motivated by sensor networks, we want that each layer is spanning and plane, and that no edge is…

The weighted spanning tree enumerator of a graph $G$ with weighted edges is the sum of the products of edge weights over all the spanning trees in $G$. In the special case that all of the edge weights equal $1$, the weighted spanning tree…

Combinatorics · Mathematics 2019-09-04 Steven Klee , Matthew T. Stamps

A sparse graph that preserves an approximation of the shortest paths between all pairs of points in a plane is called a geometric spanner. Using range trees of sublinear size, we design an algorithm in massively parallel computation (MPC)…

Computational Geometry · Computer Science 2023-08-30 Sepideh Aghamolaei , Mohammad Ghodsi

Short spanning trees subject to additional constraints are important building blocks in various approximation algorithms. Especially in the context of the Traveling Salesman Problem (TSP), new techniques for finding spanning trees with…

Data Structures and Algorithms · Computer Science 2023-09-13 Martin Nägele , Rico Zenklusen

Consider a connected graph $G$ and let $T$ be a spanning tree of $G$. Every edge $e \in G-T$ induces a cycle in $T \cup \{e\}$. The intersection of two distinct such cycles is the set of edges of $T$ that belong to both cycles. We consider…

Discrete Mathematics · Computer Science 2024-04-23 Manuel Dubinsky , César Massri , Gabriel Taubin

Let $T$ be a tree, a vertex of degree one is called a leaf. The set of leaves of $T$ is denoted by $Leaf(T)$. The subtree $T-Leaf(T)$ of $T$ is called the stem of $T$ and denoted by $Stem(T).$ In this note, we give a sharp sufficient…

Combinatorics · Mathematics 2018-10-22 Pham Hoang Ha , Dang Dinh Hanh
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