Results 11 to 20 of about 4,824 (216)

Ideal-quasi-Cauchy sequences [PDF]

open access: yes, 2012
An ideal $I$ is a family of subsets of positive integers $\textbf{N}$ which is closed under taking finite unions and subsets of its elements.
Cakalli, Huseyin, Hazarika, Bipan
core   +2 more sources

A bounded consistency theorem for strong summabilities

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1989
The study of R-type summability methods is continued in this paper by showing that two such methods are identical on the bounded portion of the strong summability field associated with the methods.
C. S. Chun, A. R. Freedman
doaj   +1 more source

Summability Methods for Oscillation of Linear Second-Order Matrix Differential Equations

open access: yesRocky Mountain Journal of Mathematics, 1993
The oscillation criteria of Wintner and Hartman for the equation \(Y''+ q(t)y=0\) on \([0,\infty)\) using limits of the mean \((1/t)\int^ t_ 0\left(\int^ s_ 0 q(u)du\right)ds\) have been extended in many ways. Other extensions of the scalar results have been made to the matrix equation \(Y''+ Q(t)= 0\) and to the selfadjoint matrix equation (1) \((PY')'
Coles, William J., Kinyon, Michael K.
openaire   +3 more sources

Summability methods based on the Riemann Zeta function

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1988
This paper is a study of summability methods that are based on the Riemann Zeta function. A limitation theorem is proved which gives a necessary condition for a sequence x to be zeta summable.
Larry K. Chu
doaj   +1 more source

Resumming the string perturbation series [PDF]

open access: yes, 2015
We use the AdS/CFT correspondence to study the resummation of a perturbative genus expansion appearing in the type II superstring dual of ABJM theory.
Grassi, Alba   +2 more
core   +3 more sources

Matrix transformations from absolutely convergent series to convergent sequences as general weighted mean summability methods

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2000
We prove the necessary and sufficient conditions for an infinity matrix to be a mapping, from absolutely convergent series to convergent sequences, which is treated as general weighted mean summability methods.
Jinlu Li
doaj   +1 more source

Approximation of Analytic Functions by Universal Vallee-Poussin Sums on the Chebyshev Polynomials

open access: yesИзвестия Иркутского государственного университета: Серия "Математика", 2018
As it is known, Chebyshev polynomials provide the best uniform approach of a function. They are a special case of Faber polynomials. A. I. Shvay (1973) proved that the Vallee-Poussin sums are the best approach apparatus in comparison with the partial ...
L.K. Dodunova, A.A. Ageikin
doaj   +1 more source

Approximation of high-dimensional parametric PDEs [PDF]

open access: yes, 2015
Parametrized families of PDEs arise in various contexts such as inverse problems, control and optimization, risk assessment, and uncertainty quantification. In most of these applications, the number of parameters is large or perhaps even infinite.
Cohen, Albert, Devore, Ronald
core   +4 more sources

Uniqueness of the Fock quantization of scalar fields in spatially flat cosmological spacetimes [PDF]

open access: yes, 2012
We study the Fock quantization of scalar fields in (generically) time dependent scenarios, focusing on the case in which the field propagation occurs in --either a background or effective-- spacetime with spatial sections of flat compact topology.
Blas, Daniel Martín-de   +4 more
core   +3 more sources

Constructive Field Theory in Zero Dimension

open access: yes, 2009
In this pedagogical note we propose to wander through five different methods to compute the number of connected graphs of the zero-dimensional $\phi^4$ field theory,in increasing order of sophistication.
Rivasseau, V.
core   +5 more sources

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