Results 51 to 60 of about 3,384,024 (197)
Forbidden substructures: induced subgraphs, Ramsey games, and sparse hypergraphs [PDF]
, 2012 We study problems in extremal combinatorics with respect to forbidden induced subgraphs, forbidden colored subgraphs, and forbidden subgraphs. In Chapter 2, we determine exactly which graphs H have the property that almost every H-free graph has a vertex
Butterfield, Jane
core
Chromatic Ramsey Numbers and Two‐Color Turán Densities
Journal 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
Small clique number graphs with three trivial critical ideals
Special Matrices, 2018 The critical ideals of a graph are the determinantal ideals of the generalized Laplacian matrix associated to a graph. Previously, they have been used in the understanding and characterizing of the graphs with critical group with few invariant factors ...
Alfaro Carlos A., Valencia Carlos E.
doaj +1 more source
Flexible List Coloring of Graphs With Maximum Average Degree Less Than 3
Journal 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
Forbidden induced subgraph of the Comparability Graph and Three Colored Posets
, 2018 The cover-incomparability graph of a poset P is the edge-union of the covering and the incomparability graph of P. As a continuation of the study of 3-colored diagrams we characterize some forbidden ⊲ - preserving subposets of the posets whose cover ...
Sibi C Babu, Baiju Sukumaran, Athul T B
core +1 more source
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
Forbidden induced subgraphs for line graphs
Discrete Mathematics, 1994 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire +3 more sources
Forbidden induced subgraphs for star-free graphs
Discrete Mathematics, 2011 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Jun Fujisawa +3 more
openaire +1 more source
Saturated Partial Embeddings of Planar Graphs
Journal of Graph Theory, EarlyView.ABSTRACT In this work, we study how far one can deviate from optimal behavior when embedding a planar graph. For a planar graph G $G$, we say that a plane subgraph H ⊆ G $H\subseteq G$ is a plane‐saturated subgraph if adding any edge (possibly with new vertices) to H $H$ would either violate planarity or make the resulting graph no longer a subgraph of
Alexander Clifton, Nika Salia
wiley +1 more source
Forbidden induced subgraphs for near perfect matchings
Discrete Mathematics, 2013 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Katsuhiro Ota +2 more
openaire +3 more sources