Results 11 to 20 of about 419 (64)

Variantes del problema del cartero mixto que se pueden resolver usando programación lineal

open access: yesRevista de Matemática: Teoría y Aplicaciones, 2012
Dada una gráfica mixta y conexa con costos en sus aristas y arcos, el problema del cartero mixto consiste en encontrar un circuito cerrado de la gráfica mixta que recorra sus aristas y arcos a costo mínimo. Se sabe que este problema es NP-duro.
Francisco Javier Zaragoza Martínez   +1 more
doaj   +2 more sources

Sparse Kneser graphs are Hamiltonian

open access: yesJournal of the London Mathematical Society, Volume 103, Issue 4, Page 1253-1275, June 2021., 2021
Abstract For integers k⩾1 and n⩾2k+1, the Kneser graph K(n,k) is the graph whose vertices are the k‐element subsets of {1,…,n} and whose edges connect pairs of subsets that are disjoint. The Kneser graphs of the form K(2k+1,k) are also known as the odd graphs.
Torsten Mütze   +2 more
wiley   +1 more source

Toughness, Forbidden Subgraphs, and Hamilton-Connected Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2022
A graph G is called Hamilton-connected if for every pair of distinct vertices {u, v} of G there exists a Hamilton path in G that connects u and v. A graph G is said to be t-tough if t·ω(G − X) ≤ |X| for all X ⊆ V (G) with ω(G − X) > 1. The toughness of G,
Zheng Wei, Broersma Hajo, Wang Ligong
doaj   +1 more source

On Implicit Heavy Subgraphs and Hamiltonicity of 2-Connected Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A graph G of order n is implicit claw-heavy if in every induced copy of K1,3 in G there are two non-adjacent vertices with sum of their implicit degrees at least n. We study various implicit degree conditions (including, but not limiting to, Ore- and Fan-
Zheng Wei, Wideł Wojciech, Wang Ligong
doaj   +1 more source

On Order Prime Divisor Graphs of Finite Groups

open access: yesDiscussiones Mathematicae - General Algebra and Applications, 2021
The order prime divisor graph 𝒫𝒟(G) of a finite group G is a simple graph whose vertex set is G and two vertices a, b ∈ G are adjacent if and only if either ab = e or o(ab) is some prime number, where e is the identity element of the group G and o(x ...
Sen Mridul K.   +2 more
doaj   +1 more source

Decomposing tournaments into paths

open access: yesProceedings of the London Mathematical Society, Volume 121, Issue 2, Page 426-461, August 2020., 2020
Abstract We consider a generalisation of Kelly's conjecture which is due to Alspach, Mason, and Pullman from 1976. Kelly's conjecture states that every regular tournament has an edge decomposition into Hamilton cycles, and this was proved by Kühn and Osthus for large tournaments. The conjecture of Alspach, Mason, and Pullman asks for the minimum number
Allan Lo   +3 more
wiley   +1 more source

The H-force sets of the graphs satisfying the condition of Ore’s theorem

open access: yesOpen Mathematics, 2020
Let G be a Hamiltonian graph. A nonempty vertex set X⊆V(G)X\subseteq V(G) is called a Hamiltonian cycle enforcing set (in short, an H-force set) of G if every X-cycle of G (i.e., a cycle of G containing all vertices of X) is a Hamiltonian cycle.
Zhang Xinhong, Li Ruijuan
doaj   +1 more source

Asymptotically sharpening the $s$-Hamiltonian index bound [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2022
For a non-negative integer $s\le |V(G)|-3$, a graph $G$ is $s$-Hamiltonian if the removal of any $k\le s$ vertices results in a Hamiltonian graph. Given a connected simple graph $G$ that is not isomorphic to a path, a cycle, or a $K_{1,3}$, let $\delta(G)
Sulin Song   +3 more
doaj   +1 more source

Forbidden Subgraphs for Existences of (Connected) 2-Factors of a Graph

open access: yesDiscussiones Mathematicae Graph Theory, 2023
Clearly, having a 2-factor in a graph is a necessary condition for a graph to be hamiltonian, while having an even factor in graph is a necessary condition for a graph to have a 2-factor.
Yang Xiaojing, Xiong Liming
doaj   +1 more source

2-generated Cayley digraphs on nilpotent groups have hamiltonian paths [PDF]

open access: yes, 2011
Suppose G is a nilpotent, finite group. We show that if {a,b} is any 2-element generating set of G, then the corresponding Cayley digraph Cay(G;a,b) has a hamiltonian path.
Morris, Dave Witte
core   +3 more sources

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