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Mostrando ítems 11-20 de 35
Artículo
On higher dimensional cocyclic Hadamard matrices
(2015)
Provided that a cohomological model for G is known, we describe a method for constructing a basis for n-cocycles over G, from which the whole set of n-dimensional n-cocyclic matrices over G may be straightforwardly calculated. ...
Artículo
A System of Equations for Describing Cocyclic Hadamard Matrices
(Wiley, 2008)
Given a basis equation image for 2-cocycles equation image over a group G of order equation image, we describe a nonlinear system of 4t-1 equations and k indeterminates equation image over equation image, whose solutions ...
Artículo
The homological reduction method for computing cocyclic Hadamard matrices
(2009)
An alternate method for constructing (Hadamard) cocyclic matrices over a finite group GG is described. Provided that a homological model View the MathML sourceB̄(Z[G])ϕ:⇌HFhG for GG is known, the homological reduction ...
Artículo
Algorithms in Algebraic Topology and Homological Algebra: Problem of Complexity
(Springer, 2002)
This review tackles the problem of the high computational complexity lying in most algorithms in algebraic topology and homological algebra. Three particular algorithms are considered: the computation of the homology of ...
Artículo
Generalized partially bent functions, generalized perfect arrays, and cocyclic Butson matrices
(Springer, 2023-08-23)
In a recent survey, Schmidt compiled equivalences between generalized bent functions, group invariant Butson Hadamard matrices, and abelian splitting relative difference sets. We establish a broader network of equivalences ...
Artículo
GA Based Robust Blind Digital Watermarking
(Elsevier, 2018)
A genetic algorithm based robust blind digital watermarking scheme is presented. The experimental results show that our scheme keeps invisibility, security and robustness more likely than other proposals in the literature, ...
Artículo
Generating binary partial Hadamard matrices
(Elsevier, 2019)
This paper deals with partial binary Hadamard matrices. Although there is a fast simple way to generate about a half (which is the best asymptotic bound known so far, see de Launey (2000) and de Launey and Gordon (2001)) ...
Artículo
On quasi-orthogonal cocycles
(Wiley, 2017)
We introduce the notion of quasi-orthogonal cocycle. This is motivated in part by the maximal determinant problem for square {±1}-matrices of size congruent to 2 modulo 4. Quasi-orthogonal cocycles are analogous to the ...
Artículo
Embedding cocylic D-optimal designs in cocylic Hadamard matrices
(International Linear Algebra Society, 2012)
A method for embedding cocyclic submatrices with “large” determinants of orders 2t in certain cocyclic Hadamard matrices of orders 4t is described (t an odd integer). If these determinants attain the largest possible ...
Artículo
Cartan's contructions and the twisted Eilenberg-Zilber theorem
(De Gruyter, 2010)