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Related papers: A short note on graphs with long Thomason's chains

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We determine the number of labelled chordal planar graphs with $n$ vertices, which is asymptotically $c_1\cdot n^{-5/2} \gamma^n n!$ for a constant $c_1>0$ and $\gamma \approx 11.89235$. We also determine the number of rooted simple chordal…

Combinatorics · Mathematics 2022-04-12 Jordi Castellví , Marc Noy , Clément Requilé

We improve by an exponential factor the lower bound of Korner and Muzi for the cardinality of the largest family of Hamilton paths in a complete graph of n vertices in which the union of any two paths has degree 4. The improvement is…

Combinatorics · Mathematics 2015-05-05 Janos Korner , Angelo Monti

We first prove a one-to-one correspondence between finding Hamiltonian cycles in a cubic planar graphs and finding trees with specific properties in dual graphs. Using this information, we construct an exact algorithm for finding…

Combinatorics · Mathematics 2015-12-07 Bohao Yao , Charl Ras , Hamid Mokhtar

Thomassen conjectured that triangle-free planar graphs have exponentially many 3-colorings. Recently, he disproved his conjecture by providing examples of such graphs with $n$ vertices and at most $2^{15n/\log_2 n}$ 3-colorings. We improve…

Combinatorics · Mathematics 2021-08-31 Zdeněk Dvořák , Luke Postle

We restate Thomassen's theorem of 3-extendability, an extension of the famous planar 5-choosability theorem, in terms of graph polynomials. This yields an Alon--Tarsi equivalent of 3-extendability.

Combinatorics · Mathematics 2023-11-23 Przemysław Gordinowicz , Paweł Twardowski

C. Thomassen in \cite{[11]} suggested (see also \cite{[2]}, J. C.Bermond, C. Thomassen, Cycles in Digraphs - A survey, J. Graph Theory 5 (1981) 1-43, Conjectures 1.6.7 and 1.6.8) the following conjectures : 1. Every 3-strongly connected…

Combinatorics · Mathematics 2018-01-17 S. Kh. Darbinyan

We propose an effective algorithm that enumerates (and actually finds) all 3-edge colorings and Hamiltonian cycles in a cubic graph. The idea is to make a preliminary run that separates the vertices into two types: ``rigid'' (such that the…

Combinatorics · Mathematics 2009-09-29 V. Ejov , N. Pugacheva , S. Rossomakhine , P. Zograf

A non-planar graph is almost-planar if either deleting or contracting any edge makes it planar. A graph with $n$ vertices is pancyclic if it contains a cycle of every length from $3$ to $n$, and it is Hamiltonian if it contains a cycle of…

Combinatorics · Mathematics 2024-10-29 Santiago T. Adams , S. R. Kingan

We show that every sufficiently large oriented graph with minimum in- and outdegree at least (3n-4)/8 contains a Hamilton cycle. This is best possible and solves a problem of Thomassen from 1979.

Combinatorics · Mathematics 2014-02-26 Peter Keevash , Daniela Kühn , Deryk Osthus

We revisit results obtained in [F. Harary, U. Peled, Hamiltonian threshold graphs, Discrete Appl.~Math., 16 (1987), 11--15], where several necessary and necessary and sufficient conditions for a connected threshold graph to be Hamiltonian…

Combinatorics · Mathematics 2021-02-17 Milica Andelic , Tamara Koledin , Zoran Stanic

We propose an improved algorithm for counting the number of Hamiltonian cycles in a directed graph. The basic idea of the method is sequential acceptance/rejection, which is successfully used in approximating the number of perfect matchings…

Data Structures and Algorithms · Computer Science 2009-11-23 Jinshan Zhang

We show that every triangulation (maximal planar graph) on $n\ge 6$ vertices can be flipped into a Hamiltonian triangulation using a sequence of less than $n/2$ combinatorial edge flips. The previously best upper bound uses $4$-connectivity…

Computational Geometry · Computer Science 2016-11-14 Jean Cardinal , Michael Hoffmann , Vincent Kusters , Csaba D. Tóth , Manuel Wettstein

Fullerene graphs, i.e., 3-connected planar cubic graphs with pentagonal and hexagonal faces, are conjectured to be Hamiltonian. This is a special case of a conjecture of Barnette and Goodey, stating that 3-connected planar graphs with faces…

Combinatorics · Mathematics 2017-08-18 František Kardoš

Motivated by trying to understand the behavior of the simplex method, Athanasiadis, De Loera and Zhang provided upper and lower bounds on the number of the monotone paths on 3-polytopes. For simple 3-polytopes with $2n$ vertices, they…

Combinatorics · Mathematics 2025-08-05 François Clément , Dan Guyer

We prove that if an $n$-vertex graph with minimum degree at least $3$ contains a Hamiltonian cycle, then it contains another cycle of length $n-o(n)$; this implies, in particular, that a well-known conjecture of Sheehan from 1975 holds…

Combinatorics · Mathematics 2017-09-19 António Girão , Teeradej Kittipassorn , Bhargav Narayanan

For $d \ge 2$, we show that all graphs of $d$-polytopes have a Hamiltonian line graph if and only if $d \ne 3$: We exhibit a graph of a $3$-polytope on $252$ vertices whose line graph does not even have Hamiltonian paths. Adapting a…

Combinatorics · Mathematics 2025-07-03 Bruno Benedetti , Marta Pavelka

Motivated by Thomassen's well-known line graph conjecture, many researchers have explored sufficient conditions for claw-free graphs to be Hamiltonian or Hamilton-connected. In 1994, Ageev proved that every $2$-connected claw-free graph…

Combinatorics · Mathematics 2026-03-05 Kenta Ozeki , Leilei Zhang

It is known that if G is a connected simple graph, then G^3 is Hamiltonian (in fact, Hamilton-connected). A simple graph is k-ordered Hamiltonian if for any sequence v_1, v_2, ..., v_k of k vertices there is a Hamiltonian cycle containing…

Combinatorics · Mathematics 2007-05-23 Denis Chebikin

We describe a construction that takes as input a graph and a basis for its first homology, and returns a triangulation of a 3-dimensional homology sphere. This makes precise an idea of M. Gromov and A. Nabutovski. The immediate application,…

Combinatorics · Mathematics 2025-09-09 Karim Adiprasito , Marc Lackenby , Juan Souto , Geva Yashfe

In this paper we consider the existence of Hamilton cycles in the random graph $G=G_{n,m}^{\delta\geq 3}$. This a random graph chosen uniformly from the set of graphs with vertex set $[n]$, $m$ edges and minimum degree at least 3. Our…

Combinatorics · Mathematics 2020-06-23 Michael Anastos , Alan Frieze