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Mostrando ítems 1-10 de 21
Artículo
Algebra Structures on the Comparison of the Reduced Bar Construction and the Reduced W-Construction
(Taylor and Francis, 2009)
For a simplicial augmented algebra K, Eilenberg–Mac Lane constructed a chain map . They proved that g is a reduction (homology isomorphism) and conjectured that it is also the injection of a contraction (special homotopy ...
Artículo
Self-Dual codes from (−1,1)-matrices of skew symmetric type
(Cornell University, 2013)
Previously, self-dual codes have been constructed from weighing matrices, and in particular from conference matrices (skew and symmetric). In this paper, codes constructed from matrices of skew symmetric type whose ...
Artículo
On Cocyclic Hadamard Matrices over Goethals-Seidel Loops
(MDPI, 2020)
About twenty-five years ago, Horadam and de Launey introduced the cocyclic development of designs, from which the notion of cocyclic Hadamard matrices developed over a group was readily derived. Much more recently, it ...
Artículo
A Mixed Heuristic for Generating Cocyclic Hadamard Matrices
(Springer, 2018)
A way of generating cocyclic Hadamard matrices is described, which combines a new heuristic, coming from a novel notion of fitness, and a peculiar local search, defined as a constraint satisfaction problem. Calculations ...
Artículo
On D4t-Cocyclic Hadamard Matrices
(Wiley, 2016)
In this paper, we describe some necessary and sufficient conditions for a set of coboundaries to yield a cocyclic Hadamard matrix over the dihedral group D4t. Using this characterization, new classification results for ...
Artículo
Determinants of (–1,1)-matrices of the skew-symmetric type: a cocyclic approach
(Walter de Gruyter GmbH, 2015)
An n by n skew-symmetric type (−1, 1)-matrix K = [ki,j ] has 1’s on the main diagonal and ±1’s elsewhere with ki,j = −kj,i. The largest possible determinant of such a matrix K is an interesting problem. The literature ...
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
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, ...