Results 41 to 50 of about 99 (66)

Distance-Local Rainbow Connection Number

open access: yesDiscussiones Mathematicae Graph Theory, 2022
Under an edge coloring (not necessarily proper), a rainbow path is a path whose edge colors are all distinct. The d-local rainbow connection number lrcd(G) (respectively, d-local strong rainbow connection number lsrcd(G)) is the smallest number of colors
Septyanto Fendy, Sugeng Kiki A.
doaj   +1 more source

Cyclic Permutations in Determining Crossing Numbers

open access: yesDiscussiones Mathematicae Graph Theory, 2022
The crossing number of a graph G is the minimum number of edge crossings over all drawings of G in the plane. Recently, the crossing numbers of join products of two graphs have been studied.
Klešč Marián, Staš Michal
doaj   +1 more source

On the planarity of line Mycielskian graph of a graph

open access: yesRatio Mathematica, 2020
The line Mycielskian graph of a graph G, denoted by Lμ(G) is defined as the graph obtained from L(G) by adding q+1 new vertices E' = ei' : 1 ≤  i ≤  q and e, then for 1 ≤  i ≤  q , joining ei' to the neighbours of ei  and  to e.
Keerthi G. Mirajkar   +1 more
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Enumeration of weighted paths on a digraph and block hook determinant

open access: yesSpecial Matrices, 2021
In this article, we evaluate determinants of “block hook” matrices, which are block matrices consist of hook matrices. In particular, we deduce that the determinant of a block hook matrix factorizes nicely.
Bera Sudip
doaj   +1 more source

On the Number of Disjoint 4-Cycles in Regular Tournaments

open access: yesDiscussiones Mathematicae Graph Theory, 2018
In this paper, we prove that for an integer r ≥ 1, every regular tournament T of degree 3r − 1 contains at least 2116r-103${{21} \over {16}}r - {{10} \over 3}$ disjoint directed 4-cycles. Our result is an improvement of Lichiardopol’s theorem when taking
Ma Fuhong, Yan Jin
doaj   +1 more source

Forbidden Pairs and (k,m)-Pancyclicity

open access: yesDiscussiones Mathematicae Graph Theory, 2017
A graph G on n vertices is said to be (k, m)-pancyclic if every set of k vertices in G is contained in a cycle of length r for each r ∈ {m, m+1, . . . , n}.
Crane Charles Brian
doaj   +1 more source

On the n-Partite Tournaments with Exactly n − m + 1 Cycles of Length m

open access: yesDiscussiones Mathematicae Graph Theory, 2021
Gutin and Rafiey [Multipartite tournaments with small number of cycles, Australas J. Combin. 34 (2006) 17–21] raised the following two problems: (1) Let m ∈ {3, 4, . . ., n}.
Guo Qiaoping, Meng Wei
doaj   +1 more source

Removable Edges on a Hamilton Cycle or Outside a Cycle in a 4-Connected Graph

open access: yesDiscussiones Mathematicae Graph Theory, 2021
Let G be a 4-connected graph. We call an edge e of G removable if the following sequence of operations results in a 4-connected graph: delete e from G; if there are vertices with degree 3 in G− e, then for each (of the at most two) such vertex x, delete ...
Wu Jichang   +3 more
doaj   +1 more source

Heavy Subgraphs, Stability and Hamiltonicity

open access: yesDiscussiones Mathematicae Graph Theory, 2017
Let G be a graph. Adopting the terminology of Broersma et al. and Čada, respectively, we say that G is 2-heavy if every induced claw (K1,3) of G contains two end-vertices each one has degree at least |V (G)|/2; and G is o-heavy if every induced claw of G
Li Binlong, Ning Bo
doaj   +1 more source

Some Results on the Independence Polynomial of Unicyclic Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2018
Let G be a simple graph on n vertices. An independent set in a graph is a set of pairwise non-adjacent vertices. The independence polynomial of G is the polynomial I(G,x)=∑k=0ns(G,k)xk$I(G,x) = \sum\nolimits_{k = 0}^n {s\left({G,k} \right)x^k }$, where s(
Oboudi Mohammad Reza
doaj   +1 more source

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