Results 111 to 120 of about 3,478,615 (190)

Line Graphs of Multigraphs and the Forbidden Graph E 6

open access: yesJournal 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

Invariant algebras and completely reducible representations [PDF]

open access: yes, 1994
We give a general construction of affine noetherian algebras with the property that every finite dimensional representation is completely reducible. Starting from enveloping algebras of semi simple Lie algebras in characteristic zero we obtain explicit ...
Kraft, Hanspeter, Small, Lance W.
core  

Spatiotemporal Evolution of Regional Heavy Rainfall Events in Guangdong, South China: Intensification and Expansion Since the Early 1990s

open access: yesInternational Journal of Climatology, EarlyView.
Regional heavy rainfall events (RHREs) in Guangdong, South China, during 1961–2025 are reassessed using an improved strength index that integrates rainfall intensity, spatial extent and duration. Results reveal a post‐1991 shift towards more frequent and spatially extensive strong and extreme events, with June showing the most pronounced ...
Wei Liu   +6 more
wiley   +1 more source

Generating Helical Polymorphic Beams Using Dielectric Metasurfaces

open access: yesLaser &Photonics Reviews, EarlyView.
Helix‐shaped polymorphic beams are optical fields whose intensity maxima spiral around the propagation axis, enabling particle manipulation through attractive or repulsive forces. Traditionally requiring expensive spatial light modulators, metasurfaces now provide a compact, cost‐effective alternative. This work demonstrates general helical polymorphic
Maryam Setareh   +3 more
wiley   +1 more source

Peskine Sixfolds and Debarre–Voisin Fourfolds With Associated Cubic Fourfolds

open access: yesMathematische 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

Invariants of automorphic lie algebras [PDF]

open access: yes
Automorphic Lie Algebras arise in the context of reduction groups introduced in the late 1970s [35] in the field of integrable systems. They are subalgebras of Lie algebras over a ring of rational functions, denied by invariance under the action of a ...
Knibbeler, Vincent
core  

Purely Coclosed G2‐Structures on Nilmanifolds—II

open access: yesMathematische 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

A Geometric Interpretation for the Algebraic Properties of Second‐Order Ordinary Differential Equations

open access: yesMathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6912-6917, April 2025.
ABSTRACT Nowadays, a substantial portion of investigations concerning the symmetry analysis of differential equations predominantly adhere to a framework comprising the following key procedures: (i) the derivation of symmetries, (ii) the determination of an optimal system, (iii) the utilization of these symmetries to construct invariants or ...
A. Paliathanasis   +2 more
wiley   +1 more source

Fragmentation–Coagulation Processes With Advection or Diffusion in Space

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT In this paper, we consider a continuous fragmentation–coagulation model in which the reacting particles can be transported in physical space through either advection or diffusion. We prove new results on the generation of C0$$ {C}_0 $$‐semigroups with parameter and use them to show that the abstract Cauchy problem associated with a more ...
Jacek Banasiak, Nduduzo Majozi
wiley   +1 more source

Order preserving limits of finite-dimensional nest algebras. [PDF]

open access: yes, 2002
We introduce order conserving embeddings as a more general form of order preserving embeddings between finite dimensional nest algebras. The structure of these embeddings is determined, in terms of order indecomposable decompositions, and they are shown ...
Alan Hopenwasser   +3 more
core  

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