Results 91 to 100 of about 1,068 (262)
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
Second-order duality for minimax fractional programming involving generalised Type-I functions [PDF]
Maejo International Journal of Science and Technology, 2013 A class of minimax fractional programming problem and its two types of second-order dual models are considered with an establishment of weak, strong and strict converse duality theorems from a view point of generalised convexity.
Anurag Jayswal
doaj
Lagrangian Duality for Multiobjective Programming Problems in Lexicographic Order
Abstract and Applied Analysis, 2013 This paper deals with a constraint multiobjective programming problem and its dual problem in the lexicographic order. We establish some duality theorems and present several existence results of a Lagrange multiplier and a lexicographic saddle point ...
X. F. Hu, L. N. Wang
doaj +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 +3 more
wiley +1 more source
Journal of Graph Theory, EarlyView.ABSTRACT Lovász et al. proved that every six‐edge‐connected graph has a nowhere‐zero three‐flow. In fact, they proved a more technical statement, which says that there exists a nowhere‐zero three‐flow that extends the flow prescribed on the incident edges of a single vertex z $z$ with bounded degree. We extend this theorem of Lovász et al.
Arnbjörg Soffía Árnadóttir +5 more
wiley +1 more source
A Complex‐Frequency Framework for Kerker Unidirectionality in Photonic Resonators
Laser &Photonics Reviews, EarlyView.ABSTRACT Electromagnetic scattering exhibits various anomalous behaviors, such as forward or backward scattering effects known as the Kerker conditions. These anomalies appear in non‐Hermitian photonic resonators and are mathematically described by operators with complex eigenfrequencies.
Loubnan Abou Hamdan +8 more
wiley +1 more source
Laser &Photonics Reviews, EarlyView.Nonlocal leaky mode metasurfaces reconstruct multiplexed holograms directly from unfiltered thermal light. High‐Q leaky guided modes compress broadband halogen emission into narrowband channels, enhancing temporal coherence a hundredfold, while a single nanohole array encodes independent images addressed by mode, angle, and polarization, establishing ...
Rajat Kumar Sinha, Mo Mojahedi
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Regularity Estimates for Fully Nonlinear Dead‐Core Problems With a Hamiltonian Term
Mathematische Nachrichten, EarlyView.ABSTRACT In this paper, we present a problem involving fully nonlinear elliptic operators with Hamiltonian, which can present a singularity or degenerate as the gradient approaches the origin. The model studied here, allows the appearance of plateau zones, i.e., unknown regions of the domain in which the non‐negative solutions vanishes.
Rafael R. Costa, Ginaldo S. Sá
wiley +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 +3 more
wiley +1 more source
Purely Coclosed G2‐Structures on Nilmanifolds—II
Mathematische Nachrichten, EarlyView.ABSTRACT This paper completes the classification of seven‐dimensional nilpotent Lie groups endowed with a left‐invariant purely coclosed G2$\text{G}_2$‐structure, initiated in Bazzoni et al. [Mathematische Nachrichten 296 no. 6 (2023): 2236–2257], the authors provided the classification of decomposable seven‐dimensional nilpotent Lie groups and of the ...
Giovanni Bazzoni, Giorgia Petracci
wiley +1 more source