Results 31 to 40 of about 60,707 (240)

The Strong 3-Rainbow Index of Graphs Containing Three Cycles

open access: yesInPrime, 2023
The concept of a strong k-rainbow index is a generalization of a strong rainbow connection number, which has an interesting application in security systems in a communication network.
Zata Yumni Awanis
doaj   +1 more source

A Victorian Age Proof of the Four Color Theorem [PDF]

open access: yes, 2010
In this paper we have investigated some old issues concerning four color map problem. We have given a general method for constructing counter-examples to Kempe's proof of the four color theorem and then show that all counterexamples can be rule out by re-
Cahit, I.
core   +1 more source

Characterizations of Graphs Having Large Proper Connection Numbers

open access: yesDiscussiones Mathematicae Graph Theory, 2016
Let G be an edge-colored connected graph. A path P is a proper path in G if no two adjacent edges of P are colored the same. If P is a proper u − v path of length d(u, v), then P is a proper u − v geodesic. An edge coloring c is a proper-path coloring of
Lumduanhom Chira   +2 more
doaj   +1 more source

On Proper (Strong) Rainbow Connection of Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A path in an edge-colored graph G is called a rainbow path if no two edges on the path have the same color. The graph G is called rainbow connected if between every pair of distinct vertices of G, there is a rainbow path.
Jiang Hui   +3 more
doaj   +1 more source

Strong edge colorings of uniform graphs

open access: yesDiscrete Mathematics, 2004
A strong edge coloring of a graph is a (proper) edge coloring in which every color class is an induced matching. The strong chromatic index \(\chi_S(G)\) of a graph \(G\) is the minimum number of colors in a strong edge coloring of \(G\). For a bipartite graph \(G=(U\cup V, E)\), and for two nonempty sets \(U'\subseteq U\) and \(V'\subseteq V\), let ...
Andrzej Czygrinow, Brendan Nagle
openaire   +1 more source

Some Equal Degree Graph Edge Chromatic Number

open access: yesMATEC Web of Conferences, 2016
Let G(V, E) be a simple graph and k is a positive integer, if it exists a mapping of f, and satisfied with f(e1)≠6 = f(e2) for two incident edges e1,e2∉E(G), f(e1)≠6=f(e2), then f is called the k-proper-edge coloring of G(k-PEC for short).
Liu Jun   +4 more
doaj   +1 more source

The strong chromatic index of 1-planar graphs [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science
The chromatic index $\chi'(G)$ of a graph $G$ is the smallest $k$ for which $G$ admits an edge $k$-coloring such that any two adjacent edges have distinct colors.
Yiqiao Wang   +3 more
doaj   +1 more source

Strong Edge Coloring of Cayley Graphs and Some Product Graphs [PDF]

open access: yesGraphs and Combinatorics, 2022
AbstractA strong edge coloring of a graph G is a proper edge coloring of G such that every color class is an induced matching. The minimum number of colors required is termed the strong chromatic index. In this paper we determine the exact value of the strong chromatic index of all unitary Cayley graphs.
Suresh Dara 0002   +3 more
openaire   +2 more sources

All finite transitive graphs admit self-adjoint free semigroupoid algebras

open access: yes, 2020
In this paper we show that every non-cycle finite transitive directed graph has a Cuntz-Krieger family whose WOT-closed algebra is $B(\mathcal{H})$. This is accomplished through a new construction that reduces this problem to in-degree $2$-regular graphs,
Dor-On, Adam, Linden, Christopher
core   +1 more source

Strong Chromatic Index Of Planar Graphs With Large Girth

open access: yesDiscussiones Mathematicae Graph Theory, 2014
Let Δ ≥ 4 be an integer. In this note, we prove that every planar graph with maximum degree Δ and girth at least 1 Δ+46 is strong (2Δ−1)-edgecolorable, that is best possible (in terms of number of colors) as soon as G contains two adjacent vertices of ...
Jennhwa Chang Gerard   +3 more
doaj   +1 more source

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