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In this article, we look into the tree gonality of genus $3$ metric graphs $\Gamma$ which is defined as the minimum of degrees of all tropical morphisms from any tropical modification of $\Gamma$ to any metric tree. It is denoted by…

Algebraic Geometry · Mathematics 2023-01-06 Hamdi Dërvodeli

Tree-cut width is a graph parameter introduced by Wollan that is an analogue of treewidth for the immersion order on graphs in the following sense: the tree-cut width of a graph is functionally equivalent to the largest size of a wall that…

Combinatorics · Mathematics 2022-08-12 Łukasz Bożyk , Oscar Defrain , Karolina Okrasa , Michał Pilipczuk

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

While the notion of arboricity of a graph is well-known in graph theory, very few results are dedicated to the minimal number of trees covering the edges of a graph, called the tree number of a graph.

Discrete Mathematics · Computer Science 2020-08-03 Natalia Vanetik

The treewidth boundedness problem for a logic asks for the existence of an upper bound on the treewidth of the models of a given formula in that logic. This problem is found to be undecidable for first order logic. We consider a…

Logic in Computer Science · Computer Science 2024-05-20 Marius Bozga , Lucas Bueri , Radu Iosif , Florian Zuleger

This work presents novel algorithms for learning Bayesian network structures with bounded treewidth. Both exact and approximate methods are developed. The exact method combines mixed-integer linear programming formulations for structure…

Artificial Intelligence · Computer Science 2014-06-09 Siqi Nie , Denis Deratani Maua , Cassio Polpo de Campos , Qiang Ji

Two dimensional rook graphs are the Cartesian product of two complete graphs. In this paper we prove that the gonality of these graphs is the expected value of $(n-1)m$ where $n$ is the size of the smaller complete graph and $m$ is the size…

Combinatorics · Mathematics 2022-05-24 Noah Speeter

Hypergraph width measures are a class of hypergraph invariants important in studying the complexity of constraint satisfaction problems (CSPs). We present a general exact exponential algorithm for a large variety of these measures. A…

Computational Complexity · Computer Science 2011-06-24 Lukas Moll , Siamak Tazari , Marc Thurley

A one-degree-of-freedom graph is a graph obtained from a minimally rigid graph in the plane and removing an edge. For such graph, the set of realisations with fixed edge length, modulo rotations and reflections, is an algebraic curve. The…

Algebraic Geometry · Mathematics 2026-03-13 Josef Schicho , Ayush Kumar Tewari , Audie Warren

We study chip-firing games on multigraphs whose underlying simple graphs are trees, paths, and stars, denoted as banana trees, paths, and stars respectively. We present a polynomial time algorithm to compute the divisorial gonality of…

We derive a quadratic-time algorithm for the genus distribution of any 3-regular, biconnected series-parallel graph, which we extend to any biconnected series-parallel graph of maximum degree at most 3. Since the biconnected components of…

Discrete Mathematics · Computer Science 2014-07-31 Jonathan L. Gross , Michal Kotrbčík , Timothy Sun

We continue the study of $(tw,\omega)$-bounded graph classes, that is, hereditary graph classes in which large treewidth is witnessed by the presence of a large clique, and the relation of this property to boundedness of the…

Combinatorics · Mathematics 2025-05-20 Claire Hilaire , Martin Milanič , Đorđe Vasić

We introduce structured decompositions, category-theoretic structures which simultaneously generalize notions from graph theory (including treewidth, layered treewidth, co-treewidth, graph decomposition width, tree independence number,…

Category Theory · Mathematics 2025-05-21 Benjamin Merlin Bumpus , Zoltan A. Kocsis , Jade Edenstar Master , Emilio Minichiello

In Chordal/Interval Vertex Deletion we ask how many vertices one needs to remove from a graph to make it chordal (respectively: interval). We study these problems under the parameterization by treewidth $tw$ of the input graph $G$. On the…

Data Structures and Algorithms · Computer Science 2025-01-31 Michal Wlodarczyk

The notion of treewidth, introduced by Robertson and Seymour in their seminal Graph Minors series, turned out to have tremendous impact on graph algorithmics. Many hard computational problems on graphs turn out to be efficiently solvable in…

Data Structures and Algorithms · Computer Science 2019-09-24 Michał Ziobro , Marcin Pilipczuk

Arboreal networks are a generalization of rooted trees, defined by keeping the tree-like structure, but dropping the requirement for a single root. Just as the class of cographs is precisely the class of undirected graphs that can be…

Combinatorics · Mathematics 2025-02-13 Guillaume E. Scholz

The notion of a braided chord diagram is introduced and studied. An equivalence relation is given which identifies all braidings of a fixed chord diagram. It is shown that finite-type invariants are stratified by braid index for knots which…

Geometric Topology · Mathematics 2007-05-23 Joan S. Birman , Rolland Trapp

Monoidal width was recently introduced by the authors as a measure of the complexity of decomposing morphisms in monoidal categories. We have shown that in a monoidal category of cospans of graphs, monoidal width and its variants can be…

Category Theory · Mathematics 2023-08-01 Elena Di Lavore , Paweł Sobociński

A rooted tree is balanced if the degree of a vertex depends only on its distance to the root. In this paper we determine the sharp threshold for the appearance of a large family of balanced spanning trees in the random geometric graph…

Combinatorics · Mathematics 2023-03-28 Alberto Espuny Díaz , Lyuben Lichev , Dieter Mitsche , Alexandra Wesolek

A graph is called (generically) rigid in $\mathbb{R}^d$ if, for any choice of sufficiently generic edge lengths, it can be embedded in $\mathbb{R}^d$ in a finite number of distinct ways, modulo rigid transformations. Here we deal with the…

Computational Geometry · Computer Science 2017-01-26 Ioannis Z. Emiris , Ioannis Psarros
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