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相关论文: Euler-genus distributions of cubic Halin graphs

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Let $\mathbb{S}_g$ be the orientable surface of genus $g$. We show that the number of vertex-labelled cubic multigraphs embeddable on $\mathbb{S}_g$ with $2n$ vertices is asymptotically $c_g n^{5(g-1)/2-1}\gamma^{2n}(2n)!$, where $\gamma$…

组合数学 · 数学 2016-04-12 Wenjie Fang , Mihyun Kang , Michael Moßhammer , Philipp Sprüssel

We derive a closed-form expression for all genus 1 Hurwitz numbers, and give a simple new graph-theoretic interpretation of Hurwitz numbers in genus 0 and 1. (Hurwitz numbers essentially count irreducible genus g covers of the sphere, with…

组合数学 · 数学 2007-05-23 Ravi Vakil

The eternal vertex cover problem is a dynamic variant of the classical vertex cover problem. It is NP-hard to compute the eternal vertex cover number of graphs and known algorithmic results for the problem are very few. This paper presents…

离散数学 · 计算机科学 2020-05-19 Jasine Babu , Veena Prabhakaran , Arko Sharma

We collect various known results (about plane curves and the moduli space of stable maps) to derive new recursive formulas enumerating low genus plane curves of any degree with various behaviors. Recursive formulas are given for the…

代数几何 · 数学 2007-05-23 Ravi Vakil

We study the problem of determining the minimal genus of a simple finite connected graph. We present an algorithm which, for an arbitrary graph $G$ with $n$ vertices and $m$ edges, determines the orientable genus of $G$ in…

离散数学 · 计算机科学 2025-07-01 Alexander Metzger , Austin Ulrigg

We define and investigate a new three-parameter family of graphs that further generalizes the Fibonacci and metallic cubes. Namely, the number of vertices in this family of graphs satisfies Horadam recurrence, a linear recurrence of second…

组合数学 · 数学 2024-10-07 Luka Podrug

We study the recognition complexity of subgraphs of k-connected planar cubic graphs for k = 1, 2, 3. We present polynomial-time algorithms to recognize subgraphs of 1- and 2-connected planar cubic graphs, both in the variable and fixed…

离散数学 · 计算机科学 2024-10-15 Miriam Goetze , Paul Jungeblut , Torsten Ueckerdt

In this paper we compute explicit formulas for the holonomy map for a gerbe with connection over an orbifold. We show that the holonomy descends to a transgression map in Deligne cohomology. We prove that this recovers both the inner local…

代数拓扑 · 数学 2015-06-26 Ernesto Lupercio , Bernardo Uribe

Genus Theory is a classical feature of integral binary quadratic forms. Using the author's generalization of the well-known correspondence between quadratic form classes and ideal classes of quadratic algebras, we extend it to the case when…

数论 · 数学 2024-04-30 William Dallaporta

This paper announces results on the behavior of some important algebraic and topological invariants --- Euler characteristic, arithmetic genus, and their intersection homology analogues; the signature, etc. --- and their associated…

代数几何 · 数学 2009-09-25 Sylvain E. Cappell , Julius L. Shaneson

We give a necessary and sufficient condition for a cubic graph to be Hamiltonian by analyzing Eulerian tours in certain spanning subgraphs of the quartic graph associated with the cubic graph by 1-factor contraction. This correspondence is…

组合数学 · 数学 2015-08-11 Simona Bonvicini , Tomaž Pisanski

In this paper, we formally introduce the concept of a row-sum matrix over an arbitrary group $G$. When $G$ is cyclic, these types of matrices have been widely used to build uniform 2-factorizations of small Cayley graphs (or, Cayley…

组合数学 · 数学 2022-09-23 A. C. Burgess , P. Danziger , A. Pastine , T. Traetta

The Hultman numbers enumerate permutations whose cycle graph has a given number of alternating cycles (they are relevant to the Bafna-Pevzner approach to genome comparison and genome rearrangements). We give two new interpretations of the…

概率论 · 数学 2011-11-15 Nikita Alexeev , Peter Zograf

A graph is unipolar if it can be partitioned into a clique and a disjoint union of cliques, and a graph is a generalised split graph if it or its complement is unipolar. A unipolar partition of a graph can be used to find efficiently the…

数据结构与算法 · 计算机科学 2016-04-05 Colin McDiarmid , Nikola Yolov

We study large uniform random maps with one face whose genus grows linearly with the number of edges. They can be seen as a model of discrete hyperbolic geometry. In the past, several of these hyperbolic geometric features have been…

组合数学 · 数学 2021-02-26 Baptiste Louf

We give a density condition for when, subject to a necessary parity condition, an eulerian graph or digraph may be cellularly embedded in an orientable surface so that it has exactly two faces, each bounded by an euler circuit, one of which…

组合数学 · 数学 2024-09-24 M. N. Ellingham , Joanna A. Ellis-Monaghan

In 1994, Thomassen proved that every planar graph is 5-list-colorable. In 1995, Thomassen proved that every planar graph of girth at least five is 3-list-colorable. His proofs naturally lead to quadratic-time algorithms to find such…

组合数学 · 数学 2019-11-07 Luke Postle

Square-tiled surfaces can be classified by their number of squares and their cylinder diagrams (also called realizable separatrix diagrams). For the case of $n$ squares and two cone points with angle $4 \pi$ each, we set up and parametrize…

几何拓扑 · 数学 2018-10-23 Sunrose T. Shrestha

We establish a set of recursion relations for the coefficients in the chromatic polynomial of a graph or a hypergraph. As an application we provide a generalization of Whitney's broken cycle theorem for hypergraphs, as well as deriving an…

组合数学 · 数学 2022-01-04 Bergfinnur Durhuus , Angelo Lucia

For two independent Erd\H{o}s-R\'enyi graphs $\mathbf G(n,p)$, we study the maximal overlap (i.e., the number of common edges) of these two graphs over all possible vertex correspondence. We present a polynomial-time algorithm which finds a…

概率论 · 数学 2022-10-17 Jian Ding , Hang Du , Shuyang Gong