Results 51 to 60 of about 793,315 (170)

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

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

Obstructions for Homomorphisms to Odd Cycles in Series‐Parallel Graphs

Journal of Graph Theory, EarlyView.
ABSTRACT For a graph H $H$, an H $H$‐colouring of a graph G $G$ is a vertex mapping ϕ : V ( G ) → V ( H ) $\phi :V(G)\to V(H)$ such that adjacent vertices are mapped to adjacent vertices. A graph G $G$ is C 2 k + 1 ${C}_{2k+1}$‐critical if G $G$ has no C 2 k + 1 ${C}_{2k+1}$‐colouring but every proper subgraph of G $G$ has a C 2 k + 1 ${C}_{2k+1 ...
Eun‐Kyung Cho, Ilkyoo Choi, Boram Park, Mark Siggers   +3 more
wiley   +1 more source

Characterization of Graphs Without Even F $F$‐Orientations

Journal of Graph Theory, EarlyView.
ABSTRACT A graph G $G$ is 1‐extendable if every edge belongs to at least one 1‐factor of G $G$. Let G $G$ be a graph with a 1‐factor F $F$. Then an even (odd) F $F$ ‐orientation of G $G$ is an orientation in which each F $F$‐alternating cycle has exactly an even (odd) number of edges directed in the same fixed direction around the cycle.
Marién Abreu, Domenico Labbate, Federico Romaniello, John Sheehan   +3 more
wiley   +1 more source

Odd Chromatic Number of Graph Classes

, 2023
International audienceA graph is called odd (respectively, even) if every vertex has odd (respectively, even) degree. Gallai proved that every graph can be partitioned into two even induced subgraphs, or into an odd and an even induced subgraph. We refer
Harutyunyan, Ararat, Melissinos, Nikolaos, Belmonte, Rémy, Köhler, Noleen   +3 more
core   +1 more source

A Structural Description of Zykov and Blanche Descartes Graphs

Journal of Graph Theory, EarlyView.
ABSTRACT Around 1950, Zykov and Blanche Descartes proposed the two first explicit constructions of triangle‐free graphs with arbitrarily large chromatic number. We define a Zykov (resp. Blanche Descartes) graph as any induced subgraph of a graph created using Zykov's construction (resp. Blanche Descartes's).
Malory Marin, Stéphan Thomassé, Nicolas Trotignon, Rémi Watrigant   +3 more
wiley   +1 more source

On odd harmonious labeling of m-shadow of cycle, gear with pendant and Shuriken graphs [PDF]

AIP Conference Proceedings, 2019
A graph G = (V(G), E(G)) with p vertices and q edges is called (p, q)-graph. An injection f is said to be odd harmonious labeling of a (p, q)-graph G if there is an injective function f from a set of vertices V(G) to a set {0, 1, 2, …, 2q − 1} such that the induced function f∗ from a set of edges E(G) to a set of odd number {1, 3, 5, … 2q − 1} defined ...
Kiki A. Sugeng, null Surip, null Rismayati   +2 more
openaire   +1 more source

Peskine Sixfolds and Debarre–Voisin Fourfolds With Associated Cubic Fourfolds

Mathematische Nachrichten, EarlyView.
ABSTRACT We develop the notion of Peskine sixfolds with associated K3 surfaces and cubic fourfolds and work out numerical conditions for when these associations occur. In discriminant 24, the first family for which there is an associated cubic fourfold, we identify the cubic explicitly.
Corey Brooke, Laure Flapan, Sarah Frei, Lisa Marquand   +3 more
wiley   +1 more source

Linear Mechatronic Modeling of Rectangular Tank Sloshing Dynamics

International Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT Sloshing dynamics in partially filled tanks can strongly influence system‐level behavior when fluid motion couples with rigid‐body dynamics. This paper presents a linear and acausal two‐dimensional sloshing model for rectangular tanks, based on the reformulation of established sloshing theory within a modular, multi‐domain modeling framework ...
Magnus Steinstø, Eilif Pedersen
wiley   +1 more source

Toward Encrypted OPF Across Transmission and Distribution—Prospects and Open Problems of Encrypted Quadratic Programming

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT The increasing integration of distributed energy resources demands enhanced coordination between transmission system operators (TSOs) and distribution system operators (DSOs) to maintain reliable grid operation. Traditional approaches rely on hierarchical or distributed optimization schemes for power flow management, but these methods either ...
Janis Adamek, Philipp Binfet, Maísa Beraldo Bandeira, Timm Faulwasser, Moritz Schulze Darup   +4 more
wiley   +1 more source