Results 41 to 50 of about 69,865 (208)

Forbidden Induced Subgraphs

open access: yesElectronic Notes in Discrete Mathematics, 2017
In descending generality I survey: five partial orderings of graphs, the induced-subgraph ordering, and examples like perfect, threshold, and mock threshold graphs. The emphasis is on how the induced subgraph ordering differs from other popular orderings and leads to different basic questions.
openaire   +2 more sources

Coloring Graphs Characterized by a Forbidden Subgraph [PDF]

open access: yesDiscrete Applied Mathematics, 2012
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Petr A. Golovach   +2 more
openaire   +7 more sources

Heavy subgraph pairs for traceability of block-chains

open access: yesDiscussiones Mathematicae Graph Theory, 2014
A graph is called traceable if it contains a Hamilton path, i.e., a path containing all its vertices. Let G be a graph on n vertices. We say that an induced subgraph of G is o−1-heavy if it contains two nonadjacent vertices which satisfy an Ore-type ...
Li Binlong   +2 more
doaj   +1 more source

On Critical Unicyclic Graphs with Cutwidth Four

open access: yesAppliedMath, 2022
The cutwidth minimization problem consists of finding an arrangement of the vertices of a graph G on a line Pn with n=|V(G)| vertices in such a way that the maximum number of overlapping edges (i.e., the congestion) is minimized.
Zhenkun Zhang, Hongjian Lai
doaj   +1 more source

Chromatic Ramsey Numbers and Two‐Color Turán Densities

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT Given a graph G, its 2‐color Turán number ex ( 2 ) ( n , G ) is the maximum number of edges in an n‐vertex graph, such that the edges can be colored with two colors avoiding a monochromatic copy of G. Let π ( 2 ) ( G ) = lim n → ∞ ex ( 2 ) ( n , G ) / n 2 be the 2‐color Turán density of G.
Maria Axenovich, Simon Gaa, Dingyuan Liu
wiley   +1 more source

Forbidden subgraphs in the norm graph

open access: yesDiscrete Mathematics, 2016
We show that the norm graph constructed in [J. Kollár, L. Rónyai and T. Szabó, Norm-graphs and bipartite Turán numbers, Combinatorica, 16 (1996) 399--406] with $n$ vertices about $\frac{1}{2}n^{2-1/t}$ edges, which contains no copy of $K_{t,(t-1)!+1}$, does not contain a copy of $K_{t+1,(t-1)!-1}$.
Ball, Simeon, PEPE, VALENTINA
openaire   +6 more sources

Forbidden subgraphs that imply hamiltonian‐connectedness* [PDF]

open access: yesJournal of Graph Theory, 2002
AbstractIt is proven that if G is a 3‐connected claw‐free graph which is also H1‐free (where H1 consists of two disjoint triangles connected by an edge), then G is hamiltonian‐connected. Also, examples will be described that determine a finite family of graphs ${\cal L}$ such that if a 3‐connected graph being claw‐free and L‐free implies G is ...
Hajo Broersma   +4 more
openaire   +2 more sources

On Sequential Heuristic Methods for the Maximum Independent Set Problem

open access: yesDiscussiones Mathematicae Graph Theory, 2017
We consider sequential heuristics methods for the Maximum Independent Set (MIS) problem. Three classical algorithms, VO [11], MIN [12], or MAX [6] , are revisited. We combine Algorithm MIN with the α-redundant vertex technique[3].
Lê Ngoc C.   +2 more
doaj   +1 more source

On the chromatic number of (P_{5},windmill)-free graphs [PDF]

open access: yesOpuscula Mathematica, 2017
In this paper we study the chromatic number of \((P_5, windmill)\)-free graphs. For integers \(r,p\geq 2\) the windmill graph \(W_{r+1}^p=K_1 \vee pK_r\) is the graph obtained by joining a single vertex (the center) to the vertices of \(p\) disjoint ...
Ingo Schiermeyer
doaj   +1 more source

Flexible List Coloring of Graphs With Maximum Average Degree Less Than 3

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT In the flexible list coloring problem, we consider a graph G $G$ and a color list assignment L $L$ on G $G$, as well as a subset U ⊆ V ( G ) $U\subseteq V(G)$ for which each u ∈ U $u\in U$ has a preferred color p ( u ) ∈ L ( u ) $p(u)\in L(u)$. Our goal is to find a proper L $L$‐coloring ϕ $\phi $ of G $G$ such that ϕ ( u ) = p ( u ) $\phi (u)=
Richard Bi, Peter Bradshaw
wiley   +1 more source

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