Results 11 to 20 of about 807 (75)

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

On Hamiltonian Cycles in Claw-Free Cubic Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2022
We show that every claw-free cubic graph of order n at least 8 has at most 2⌊n4⌋{2^{\left\lfloor {{n \over 4}} \right\rfloor }} Hamiltonian cycles, and we also characterize all extremal graphs.
Mohr Elena, Rautenbach Dieter
doaj   +1 more source

The Existence of Path-Factor Covered Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2023
A spanning subgraph H of a graph G is called a P≥k-factor of G if every component of H is isomorphic to a path of order at least k, where k ≥ 2. A graph G is called a P≥k-factor covered graph if there is a P≥k-factor of G covering e for any e ∈ E(G).
Dai Guowei
doaj   +1 more source

Equimatchable Bipartite Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2023
A graph is called equimatchable if all of its maximal matchings have the same size. Lesk et al. [Equi-matchable graphs, Graph Theory and Combinatorics (Academic Press, London, 1984) 239–254] has provided a characterization of equimatchable bipartite ...
Büyükçolak Yasemin   +2 more
doaj   +1 more source

Some Results on Path-Factor Critical Avoidable Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2023
A path factor is a spanning subgraph F of G such that every component of F is a path with at least two vertices. We write P≥k = {Pi : i ≥ k}. Then a P≥k-factor of G means a path factor in which every component admits at least k vertices, where k ≥ 2 is ...
Zhou Sizhong
doaj   +1 more source

Strong Geodetic Problem in Networks

open access: yesDiscussiones Mathematicae Graph Theory, 2020
In order to model certain social network problems, the strong geodetic problem and its related invariant, the strong geodetic number, are introduced.
Manuel Paul   +4 more
doaj   +1 more source

A Survey on Packing Colorings

open access: yesDiscussiones Mathematicae Graph Theory, 2020
If S = (a1, a2, . . .) is a non-decreasing sequence of positive integers, then an S-packing coloring of a graph G is a partition of V (G) into sets X1, X2, . . .
Brešar Boštjan   +3 more
doaj   +1 more source

Strong edge geodetic problem in networks

open access: yesOpen Mathematics, 2017
Geodesic covering problems form a widely researched topic in graph theory. One such problem is geodetic problem introduced by Harary et al. [Math. Comput. Modelling, 1993, 17, 89-95].
Manuel Paul   +4 more
doaj   +1 more source

The matching polynomial of a distance‐regular graph

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 23, Issue 2, Page 89-97, 2000., 2000
A distance‐regular graph of diameter d has 2d intersection numbers that determine many properties of graph (e.g., its spectrum). We show that the first six coefficients of the matching polynomial of a distance‐regular graph can also be determined from its intersection array, and that this is the maximum number of coefficients so determined.
Robert A. Beezer, E. J. Farrell
wiley   +1 more source

Further new results on strong resolving partitions for graphs

open access: yesOpen Mathematics, 2020
A set W of vertices of a connected graph G strongly resolves two different vertices x, y ∉ W if either d G(x, W) = d G(x, y) + d G(y, W) or d G(y, W) = d G(y, x) + d
Kuziak Dorota, Yero Ismael G.
doaj   +1 more source

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