Results 21 to 30 of about 97 (92)

Old and new generalizations of line graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 29, Page 1509-1521, 2004., 2004
Line graphs have been studied for over seventy years. In 1932, H. Whitney showed that for connected graphs, edge‐isomorphism implies isomorphism except for K3 and K1,3. The line graph transformation is one of the most widely studied of all graph transformations.
Jay Bagga
wiley   +1 more source

Picture Fuzzy Incidence Graphs with Application [PDF]

open access: yes, 2021
In this research article, we initiate the novel idea of picturefuzzy incidence graphs (PFIGs). We explain some innovative notionscomprising of picture fuzzy cut-vertices, picture fuzzy bridges, picturefuzzy incidence cutpairs, and picture fuzzy incidence
Irfan Nazeer; Department of Mathematics, University of management and technology, Lahore 54770   +1 more
core  

Minimum Edge Cuts in Diameter 2 Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
Plesnik proved that the edge connectivity and minimum degree are equal for diameter 2 graphs. We provide a streamlined proof of this fact and characterize the diameter 2 graphs with a nontrivial minimum edge cut.
Bickle Allan, Schwenk Allen
doaj   +1 more source

A measure of graph vulnerability: scattering number

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 30, Issue 1, Page 1-8, 2002., 2002
The scattering number of a graph G, denoted sc(G), is defined by sc(G) = max{c(G − S) − |S| : S⫅V(G) and c(G − S) ≠ 1} where c(G − S) denotes the number of components in G − S. It is one measure of graph vulnerability. In this paper, general results on the scattering number of a graph are considered.
Alpay Kirlangiç
wiley   +1 more source

Proper Rainbow Connection Number of Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A path in an edge-coloured graph is called a rainbow path if its edges receive pairwise distinct colours. An edge-coloured graph is said to be rainbow connected if any two distinct vertices of the graph are connected by a rainbow path.
Doan Trung Duy, Schiermeyer Ingo
doaj   +1 more source

On the acyclic point‐connectivity of the n‐cube

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 5, Issue 4, Page 737-744, 1982., 1982
The acyclic point‐connectivity of a graph G, denoted α(G), is the minimum number of points whose removal from G results in an acyclic graph. In a 1975 paper, Harary stated erroneously that α(Qn) = 2n−1 − 1 where Qn denotes the n‐cube. We prove that for n > 4, 7 · 2n−4 ≤ α(Qn) ≤ 2n−1 − 2n−y−2, where y = [log2(n − 1)].
John Banks, John Mitchem
wiley   +1 more source

Least eigenvalue of the connected graphs whose complements are cacti

open access: yesOpen Mathematics, 2019
Suppose that Γ is a graph of order n and A(Γ) = [ai,j] is its adjacency matrix such that ai,j is equal to 1 if vi is adjacent to vj and ai,j is zero otherwise, where 1 ≤ i, j ≤ n.
Wang Haiying   +4 more
doaj   +1 more source

On the Connectivity of Token Graphs of Trees [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2022
Let $k$ and $n$ be integers such that $1\leq k \leq n-1$, and let $G$ be a simple graph of order $n$. The $k$-token graph $F_k(G)$ of $G$ is the graph whose vertices are the $k$-subsets of $V(G)$, where two vertices are adjacent in $F_k(G)$ whenever ...
Ruy Fabila-Monroy   +2 more
doaj   +1 more source

Rainbow Connection Number of Graphs with Diameter 3

open access: yesDiscussiones Mathematicae Graph Theory, 2017
A path in an edge-colored graph G is rainbow if no two edges of the path are colored the same. The rainbow connection number rc(G) of G is the smallest integer k for which there exists a k-edge-coloring of G such that every pair of distinct vertices of G
Li Hengzhe, Li Xueliang, Sun Yuefang
doaj   +1 more source

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

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