Displaying similar documents to “On the statistical and σ-cores”

Regular statistical convergence of double sequences

Ferenc Móricz (2005)

Colloquium Mathematicae

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The concepts of statistical convergence of single and double sequences of complex numbers were introduced in [1] and [7], respectively. In this paper, we introduce the concept indicated in the title. A double sequence x j k : ( j , k ) ² is said to be regularly statistically convergent if (i) the double sequence x j k is statistically convergent to some ξ ∈ ℂ, (ii) the single sequence x j k : k is statistically convergent to some ξ j for each fixed j ∈ ℕ ∖ ₁, (iii) the single sequence x j k : j is statistically convergent...

A-Statistical Convergence of Subsequence of Double Sequences

Harry I. Miller (2007)

Bollettino dell'Unione Matematica Italiana

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The concept of statistical convergence of a sequence was first introduced by H. Fast [7] in 1951. Recently, in the literature, the concept of statistical convergence of double sequences has been studied. The main result in this paper is a theorem that gives meaning to the statement: s = s i j converges statistically A to L if and only if "most" of the "subsequences" of s converge to L in the ordinary sense. The results presented here are analogue of theorems in [12], [13] and [6] and are concerned...

Nested matrices and inverse M -matrices

Jeffrey L. Stuart (2015)

Czechoslovak Mathematical Journal

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Given a sequence of real or complex numbers, we construct a sequence of nested, symmetric matrices. We determine the L U - and Q R -factorizations, the determinant and the principal minors for such a matrix. When the sequence is real, positive and strictly increasing, the matrices are strictly positive, inverse M -matrices with symmetric, irreducible, tridiagonal inverses.

The space S α , β and σ-core

Bruno de Malafosse (2006)

Studia Mathematica

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We give some new properties of the space S α , β and we apply them to the σ-core theory. These results generalize those by Choudhary and Yardimci.

On the matrix negative Pell equation

Aleksander Grytczuk, Izabela Kurzydło (2009)

Discussiones Mathematicae - General Algebra and Applications

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Let N be a set of natural numbers and Z be a set of integers. Let M₂(Z) denotes the set of all 2x2 matrices with integer entries. We give necessary and suficient conditions for solvability of the matrix negative Pell equation (P) X² - dY² = -I with d ∈ N for nonsingular X,Y belonging to M₂(Z) and his generalization (Pn) i = 1 n X i - d i = 1 n Y ² i = - I with d ∈ N for nonsingular X i , Y i M ( Z ) , i=1,...,n.

Some methods of constructing kernels in statistical learning

Tomasz Górecki, Maciej Łuczak (2010)

Discussiones Mathematicae Probability and Statistics

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This paper is a collection of numerous methods and results concerning a design of kernel functions. It gives a short overview of methods of building kernels in metric spaces, especially R n and S n . However we also present a new theory. Introducing kernels was motivated by searching for non-linear patterns by using linear functions in a feature space created using a non-linear feature map.

Statistical approximation by positive linear operators

O. Duman, C. Orhan (2004)

Studia Mathematica

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Using A-statistical convergence, we prove a Korovkin type approximation theorem which concerns the problem of approximating a function f by means of a sequence Tₙ(f;x) of positive linear operators acting from a weighted space C ϱ into a weighted space B ϱ .

G-matrices, J -orthogonal matrices, and their sign patterns

Frank J. Hall, Miroslav Rozložník (2016)

Czechoslovak Mathematical Journal

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A real matrix A is a G-matrix if A is nonsingular and there exist nonsingular diagonal matrices D 1 and D 2 such that A - T = D 1 A D 2 , where A - T denotes the transpose of the inverse of A . Denote by J = diag ( ± 1 ) a diagonal (signature) matrix, each of whose diagonal entries is + 1 or - 1 . A nonsingular real matrix Q is called J -orthogonal if Q T J Q = J . Many connections are established between these matrices. In particular, a matrix A is a G-matrix if and only if A is diagonally (with positive diagonals) equivalent to a column permutation...

Vandermonde nets

Roswitha Hofer, Harald Niederreiter (2014)

Acta Arithmetica

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The second-named author recently suggested identifying the generating matrices of a digital (t,m,s)-net over the finite field q with an s × m matrix C over q m . More exactly, the entries of C are determined by interpreting the rows of the generating matrices as elements of q m . This paper introduces so-called Vandermonde nets, which correspond to Vandermonde-type matrices C, and discusses the quality parameter and the discrepancy of such nets. The methods that have been successfully used...

A computation of positive one-peak posets that are Tits-sincere

Marcin Gąsiorek, Daniel Simson (2012)

Colloquium Mathematicae

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A complete list of positive Tits-sincere one-peak posets is provided by applying combinatorial algorithms and computer calculations using Maple and Python. The problem whether any square integer matrix A ( ) is ℤ-congruent to its transpose A t r is also discussed. An affirmative answer is given for the incidence matrices C I and the Tits matrices C ̂ I of positive one-peak posets I.

Various categorical approaches to statistical spaces

Tadeusz Bromek, Maria Moszyńska

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CONTENTSIntroduction..............................................................................................................51. Preliminaries........................................................................................................61.0. Measurable, probabilistic, and statistical spaces..............................................61.1. Transition functions..........................................................................................61.2. Linear space of...

Geometry and inequalities of geometric mean

Trung Hoa Dinh, Sima Ahsani, Tin-Yau Tam (2016)

Czechoslovak Mathematical Journal

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We study some geometric properties associated with the t -geometric means A t B : = A 1 / 2 ( A - 1 / 2 B A - 1 / 2 ) t A 1 / 2 of two n × n positive definite matrices A and B . Some geodesical convexity results with respect to the Riemannian structure of the n × n positive definite matrices are obtained. Several norm inequalities with geometric mean are obtained. In particular, we generalize a recent result of Audenaert (2015). Numerical counterexamples are given for some inequality questions. A conjecture on the geometric mean inequality regarding...

On upper triangular nonnegative matrices

Yizhi Chen, Xian Zhong Zhao, Zhongzhu Liu (2015)

Czechoslovak Mathematical Journal

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We first investigate factorizations of elements of the semigroup S of upper triangular matrices with nonnegative entries and nonzero determinant, provide a formula for ρ ( S ) , and, given A S , also provide formulas for l ( A ) , L ( A ) and ρ ( A ) . As a consequence, open problem 2 and problem 4 presented in N. Baeth et al. (2011), are partly answered. Secondly, we study the semigroup of upper triangular matrices with only positive integral entries, compute some invariants of such semigroup, and also partly answer...

Linear preservers of row-dense matrices

Sara M. Motlaghian, Ali Armandnejad, Frank J. Hall (2016)

Czechoslovak Mathematical Journal

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Let 𝐌 m , n be the set of all m × n real matrices. A matrix A 𝐌 m , n is said to be row-dense if there are no zeros between two nonzero entries for every row of this matrix. We find the structure of linear functions T : 𝐌 m , n 𝐌 m , n that preserve or strongly preserve row-dense matrices, i.e., T ( A ) is row-dense whenever A is row-dense or T ( A ) is row-dense if and only if A is row-dense, respectively. Similarly, a matrix A 𝐌 n , m is called a column-dense matrix if every column of A is a column-dense vector. At the end, the structure...

Analytic aspects of the circulant Hadamard conjecture

Teodor Banica, Ion Nechita, Jean-Marc Schlenker (2014)

Annales mathématiques Blaise Pascal

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We investigate the problem of counting the real or complex Hadamard matrices which are circulant, by using analytic methods. Our main observation is the fact that for | q 0 | = ... = | q N - 1 | = 1 the quantity Φ = i + k = j + l q i q k q j q l satisfies Φ N 2 , with equality if and only if q = ( q i ) is the eigenvalue vector of a rescaled circulant complex Hadamard matrix. This suggests three analytic problems, namely: (1) the brute-force minimization of Φ , (2) the study of the critical points of Φ , and (3) the computation of the moments of Φ . We explore here...

A method to rigorously enclose eigenpairs of complex interval matrices

Castelli, Roberto, Lessard, Jean-Philippe

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In this paper, a rigorous computational method to enclose eigenpairs of complex interval matrices is proposed. Each eigenpair x = ( λ , ) is found by solving a nonlinear equation of the form f ( x ) = 0 via a contraction argument. The set-up of the method relies on the notion of r a d i i p o l y n o m i a l s , which provide an efficient mean of determining a domain on which the contraction mapping theorem is applicable.

Localization of dominant eigenpairs and planted communities by means of Frobenius inner products

Dario Fasino, Francesco Tudisco (2016)

Czechoslovak Mathematical Journal

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We propose a new localization result for the leading eigenvalue and eigenvector of a symmetric matrix A . The result exploits the Frobenius inner product between A and a given rank-one landmark matrix X . Different choices for X may be used, depending on the problem under investigation. In particular, we show that the choice where X is the all-ones matrix allows to estimate the signature of the leading eigenvector of A , generalizing previous results on Perron-Frobenius properties of matrices...