Results 121 to 130 of about 8,623,913 (295)
Line Graphs of Multigraphs and the Forbidden Graph E 6
Journal of Graph Theory, EarlyView.ABSTRACT The line graph Γ of a multigraph Δ is the graph whose vertices are the edges of Δ, where two such edges are adjacent if and only if they meet in a single vertex of Δ. We provide several characterizations of such line graphs and in particular show that a graph is a line graph if and only if it does not contain one of the 32 graphs, all of which
Hans Cuypers
wiley +1 more source
Ramsey Numbers of Connected Clique Matchings
The Electronic Journal of Combinatorics, 2017 We determine the Ramsey number of a connected clique matching. That is, we show that if $G$ is a $2$-edge-coloured complete graph on $(r^2-r-1)n-r+1$ vertices, then there is a monochromatic connected subgraph containing $n$ disjoint copies of $K_r$, and that this number of vertices cannot be reduced.
openaire +4 more sources
A Note on Extendable Sets of Colorings and Rooted Minors
Journal of Graph Theory, EarlyView.ABSTRACT DeVos and Seymour proved that for every set C $C$ of 3‐colorings of a set X $X$ of vertices, there exists a plane graph G $G$ with vertices of X $X$ incident with the outer face such that a 3‐coloring of X $X$ extends to a 3‐coloring of G $G$ if and only if it belongs to C $C$.
Zdeněk Dvořák, Jan M. Swart
wiley +1 more source
The upper chromatic number of quasi-interval co-hypergraphs
Le Matematiche, 1997 We investigate the structural and colouring properties of clique hyper-graphs of interval graphs called the quasi-interval hypergraphs. We find the conditions when they are interval hypergraphs. The upper chromatic number for the clique co-hypergraphs of
Violeta Prisakaru
doaj
Finding Large Clique Minors is Hard
Journal of Graph Algorithms and Applications, 2009 We prove that it is NP-complete, given a graph G and a parameter h, to determine whether G contains a complete graph Kh as a minor.
David Eppstein
doaj +1 more source
Equivalent Formulation of Thomassen's Conjecture Using Tutte Paths in Claw‐Free Graphs
Journal of Graph Theory, EarlyView.ABSTRACT We continue studying Thomassen's conjecture (every 4‐connected line graph has a Hamilton cycle) in the direction of a recently shown equivalence with Jackson's conjecture (every 2‐connected claw‐free graph has a Tutte cycle), and we extend the equivalent formulation as follows: In every connected claw‐free graph, any two vertices are connected
Adam Kabela +2 more
wiley +1 more source
A Note on Lovász Characterization of Perfect Graphs
Journal of Graph Theory, EarlyView.ABSTRACT A graph is perfect if, for every induced subgraph, the chromatic number equals the size of its largest clique. In 1972, Lovász established a fundamental characterization of perfect graphs, showing that a graph is perfect if and only if, for every induced subgraph, the product of the size of the largest independent set and the size of the ...
James Alex
wiley +1 more source
Disrupting the Chain of Displaced Aggression: A Review and Agenda for Future Research
Journal of Organizational Behavior, EarlyView.ABSTRACT Displaced aggression refers to instances in which a person redirects their harm‐doing behavior from a primary to a secondary, substitute target. Since the publication of the first empirical article in 1948, there has been a noticeable surge in research referencing this theory in both management and psychology journals.
Constantin Lagios +4 more
wiley +1 more source
Journal of Organizational Behavior, EarlyView.ABSTRACT Subgroups are dynamic entities evolving constantly in response to changing contexts and time. Although scholars from both the attribute and the network views have acknowledged that subgroups are inherently complex and fluid, research in these traditions has remained bifurcated, with limited efforts to integrate the two perspectives to more ...
Jinhee Moon +3 more
wiley +1 more source
AKCE International Journal of Graphs and CombinatoricsThe computation of the clique number of a graph is a fundamental problem in graph theory, which has many applications in computational chemistry, bioinformatics, computer, and social networking.
Ying Wang +5 more
doaj +1 more source