Results 291 to 300 of about 878,195 (332)

Structured null space problem

SPIE Proceedings, 1998
We present a new algorithm for finding specially structured vectors that span a null space. These vectors arise in direction finding applications for uniform rectangular antenna arrays.
Franklin T. Luk, Kai-Bor Yu
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The Null Space Problem I. Complexity

SIAM Journal on Algebraic Discrete Methods, 1986
The problem of finding basic vectors with the fewest nonzeroes, of the null space of a matrix, is shown to be characterized by a greedy algorithm. This algorithm successively augments a partial basis by a sparsest vector in the null-space. Still, the problem is NP-hard, since finding such sparsest vector is NP-complete. The related problem of finding a
Coleman, Thomas F., Pothen, Alex
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NULL HELICES IN LORENTZIAN SPACE FORMS

International Journal of Modern Physics A, 2001
In this paper we introduce a reference along a null curve in an n-dimensional Lorentzian space with the minimum number of curvatures. That reference generalizes the reference of Bonnor for null curves in Minkowski space–time and it is called the Cartan frame of the curve. The associated curvature functions are called the Cartan curvatures of the curve.
Ferrández, Angel, Giménez, Angel, Lucas, Pascual   +2 more
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Spectral-null codes and null spaces of Hadamard submatrices

Designs, Codes and Cryptography, 1994
A code-word \((c_0,\dots,c_{n-1})\) over \(\{-1,+1\}\subseteq\mathbb{R}\) is said to have an \(r\)th order spectral null at zero frequency if \(\sum_{j=0}^{n-1}j^i\cdot c_j=0\) for \(i=0,\dots,{n-1}\). The author considers codes \({\mathcal C}(m,r)\) of length \(2^m\) over \(\{-1,+1\}\) whose codewords have an \(r\)th order spectral null at zero ...
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Basic Null Space Calculations

The College Mathematics Journal, 1984
Dan Kalman studied mathematics at Harvey Mudd College, earning a B.S. in 1974, and at University of WisconsinMadison earning a Ph.D. in 1980. He has taught at Lawrence University in Appleton, Wisconsin, and is at present an assistant professor at the University of Wisconsin-Green Bay.
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)-(-Space and Null Infinity

1977
Our object in this article is to provide a review of one approach to asymptotically flat space-times, and to show how this proach leads to the introduction of an associated four complex dimensional manifold, )-(-space, with remarkable properties.
M. Ko, E. T. Newman, K. P. Tod
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Bornological spaces of null sequences

Archiv der Mathematik, 1995
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Dierolf, Susanne, Domański, Paweł
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Null generalized helices in Lorentz Minkowski spaces

Journal of Physics A: Mathematical and General, 2002
In the past few years, these three authors got us used to rich and good quality papers in the field, and this particular work is no exception. Of a significant importance in this context is the Frenet frame (and its Frenet equations) introduced by the authors along a null curve (with a minimal number of curvature functions).
Ferrández, Angel, Giménez, Angel, Lucas, Pascual   +2 more
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Null-Sets Criteria for Weighted Sobolev Spaces

Journal of Mathematical Sciences, 2003
The authors give functional, capacity and metric characterizations of null sets on weighted Sobolev spaces \(L^1_{p,w}(G)\), with \(G\) an open subset of the \(n\)-dimensional Euclidean space. The weights are the usual Muckenhoupt \(A_p\) weights, and the norm on \(L^1_{p,w}(G)\) is given by \[ \int_G | \nabla u| ^p w \, dx.
Demshin, I. N., Dymchenko, Yu. V., Shlyk, V. A.   +2 more
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Null spaces and Haar transform

Proceedings of the 2007 international conference on Computer systems and technologies - CompSysTech '07, 2007
The paper considers the first wavelet transform -- Haar one, and its connection with the orthogonal bases of the null spaces of cyclic endomorphisms -- filters. It is presented a new transform connected with the Haar transform through a bit-reversal matrix. This approach gives new possibilities of constructing fast transforms, especially a Fourier one.
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