Results 31 to 40 of about 22,128,186 (175)

Generating Geodesic Flows and Supergravity Solutions [PDF]

open access: yes, 2009
We consider the geodesic motion on the symmetric moduli spaces that arise after timelike and spacellike reductions of supergravity theories. The geodesics correspond to timelike respectively spacelike p-brane Solutions when they are lifted over a p ...
Trigiante, Mario   +10 more
core   +2 more sources

Exact Values and Bounds on Covering Schemes of Strength Two

open access: yesJournal of Combinatorial Designs, EarlyView.
ABSTRACT In this work, we investigate covering schemes of strength 2 over finite abelian groups, establishing new lower and upper bounds and evaluating new exact values. A main result is a new general lower bound that improves the trivial one and achieves optimality for the binary case. We also develop a recursive relation based on subsets of the group
André G. Castoldi   +4 more
wiley   +1 more source

W-algebras as coset vertex algebras [PDF]

open access: yes, 2019
We prove the long-standing conjecture on the coset construction of the minimal series principal W-algebras of ADE types in full generality. We do this by first establishing Feigin’s conjecture on the coset realization of the universal principal W ...
Creutzig, Thomas   +2 more
core   +1 more source

Catalan Bounds for Symmetric Strength‐Two Orthogonal Arrays

open access: yesJournal of Combinatorial Designs, EarlyView.
ABSTRACT A Hamming shell construction is a two‐level array obtained by taking every binary vector of a given Hamming weight a prescribed number of times, for each weight in turn. Such arrays are invariant under all permutations of the factors, and they are strength‐two orthogonal arrays exactly when the multiplicities satisfy three linear constraints ...
Ruwan C. Karunanayaka
wiley   +1 more source

Context‐free graphs and their transition groups

open access: yesTransactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.
Abstract Starting from context‐free inverse graphs, we introduce a new class of groups and study their structural properties. We establish closure properties, show that their coword problems are context‐free, analyze torsion elements, and realize them as subgroups of the asynchronous rational group.
Daniele D'Angeli   +3 more
wiley   +1 more source

Coset enumeration strategies

open access: yes, 1991
A primary reference on computer implementation of coset enumeration procedures is a 1973 paper of Cannon, Dimino, Havas and Watson. Programs and techniques described there are updated in this paper.
George Havas, Havas, George
core   +1 more source

Magic Coset Decompositions [PDF]

open access: yes, 2012
By exploiting a "mixed" non-symmetric Freudenthal-Rozenfeld-Tits magic square, two types of coset decompositions are analyzed for the non-compact special K\"ahler symmetric rank-3 coset E7(-25)/[(E6(-78) x U(1))/Z_3], occurring in supergravity as the ...
Cerchiai, Bianca Letizia   +4 more
core   +1 more source

Low Complexity Sub-Nyquist Wideband Spectrum Sensing for Cognitive Radio

open access: yesIEEE Access, 2018
In order to provide more available spectrum and quickly switchover, wideband spectrum sensing (WSS) is desirable for cognitive radio. Sub-Nyquist sampling is crucial for WSS to reduce energy and computational costs, while the existing algorithms based on
Jian Yang, Min Jia, Xuemai Gu, Qing Guo
doaj   +1 more source

Secret Sharing, Zero Sum Sets, and Hamming Codes

open access: yesMathematics, 2020
A (t,n)-secret sharing scheme is a method of distribution of information among n participants such that any t>1 of them can reconstruct the secret but any t−1 cannot.
Selda Çalkavur, Patrick Solé
doaj   +1 more source

Beyond Directions: Symmetry‐Aware Rotation Sets for Triaxial Diffusion Encoding by Geometric Filter Optimization

open access: yesMagnetic Resonance in Medicine, Volume 96, Issue 5, Page 2489-2504, November 2026.
ABSTRACT Purpose To improve the accuracy of diffusion‐weighted powder average signals for diffusion encoding with arbitrary b‐tensors. Methods We identify an intrinsic dihedral (D2) symmetry of diffusion signals for arbitrary diffusion encoding, which defines their natural signal space (a quotient of 3D rotations). Based on this, we propose a method to
Sune Nørhøj Jespersen   +1 more
wiley   +1 more source

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