Results 21 to 30 of about 165,935,923 (285)

Differences of Positive Linear Operators on Simplices

open access: yesJournal of Function Spaces, 2021
The aim of the paper is twofold: we introduce new positive linear operators acting on continuous functions defined on a simplex and then estimate differences involving them and/or other known operators.
Ana-Maria Acu   +2 more
doaj   +1 more source

Discrete $d$-dimensional moduli of smoothness [PDF]

open access: yesProceedings of the American Mathematical Society, 2014
We show that on the $d$-dimensional cube $I^d\equiv [0,1]^d$ the discrete moduli of smoothness which use only the values of the function on a diadic mesh are sufficient to determine the moduli of smoothness of that function. As an important special case our result implies for $f\in C(I^d)$ and given integer $r$ that when $0<α0$ and $|u|=1$ such that
Ditzian, Z., Prymak, A.
openaire   +3 more sources

Directional Moduli of Rotundity and Smoothness

open access: yes, 2021
We study various notions of directional moduli of rotundity and when such moduli of rotundity of power type imply the underlying space is superreflexive. Duality with directional moduli of smoothness and some applications are also discussed.
Giles, John R.   +2 more
core   +1 more source

On Generalized Moduli of Quasi-Banach Space

open access: yesJournal of Function Spaces, 2018
We shall discuss three generalized moduli such as generalized modulus of convexity, modulus of smoothness, and modulus of Zou-Cui of quasi-Banach spaces and give some important properties of these moduli.
Young Chel Kwun   +4 more
doaj   +1 more source

K-moduli, moduli of smoothness, and Bernstein polynomials on a simplex

open access: yesIndagationes Mathematicae, 1991
Let \(f\in C[0,1]\) and let \(B_ n(f,x)\) be the classical Bernstein polynomials associated to \(f\). The approximation behavior of \(B_ n(f,x)\) is related to the weighted \(K\)-modulus \(K_ \varphi^ 2(f,t)\), for example by \(\| B_ n f-f\|_ \infty \leq C\cdot K_ \varphi^ 2\bigl(f,{1\over{n+1}}\bigr)\). (See, for example, \textit{H.
Berens, H., Xu, Y.
openaire   +1 more source

Directional moduli of rotundity and smoothness [PDF]

open access: yes, 1999
summary:We study various notions of directional moduli of rotundity and when such moduli of rotundity of power type imply the underlying space is superreflexive.
Giles, John R.   +2 more
core   +1 more source

A new construction of Lupaş operators and its approximation properties

open access: yesAdvances in Difference Equations, 2021
The aim of this paper is to study a new generalization of Lupaş-type operators whose construction depends on a real-valued function ρ by using two sequences u m $u_{m} $ and v m $v_{m}$ of functions.
Mohd Qasim   +3 more
doaj   +1 more source

Calabi–Yau threefolds and moduli of abelian surfaces I [PDF]

open access: yes, 2001
We describe birational models and decide the rationality/unirationality of moduli spaces $\cal A$d (and $\cal A$levd) of (1, d)-polarized Abelian surfaces (with canonical level structure, respectively) for small values of d.
Sorin Popescu   +3 more
core   +1 more source

On Equivalence of Moduli of Smoothness

open access: yesJournal of Approximation Theory, 1999
It is known that if \(f \in W^k_p\), then \[ \omega_m(f,t)_p \leq t \omega_{m-1}(f',t)_p \leq \cdots. \] The inverse statement with constants independent of \(f\) is not true in general. \textit{Y. Hu} and \textit{X. Yu} [SIAM J. Numer. Anal. 32, No. 5, 1428-1435 (1995; Zbl 0841.41007)] proved that the inverse holds true for splines \(S\) with equally ...
openaire   +2 more sources

Best approximation and moduli of smoothness: Computation and equivalence theorems [PDF]

open access: yes, 2008
In this paper we investigate the trigonometric series with the β-general monotone coefficients. First, we study the uniform convergence criterion. The estimates of best approximations and moduli of smoothness of the series in uniform metrics are obtained
Tikhonov, Sergey
core   +1 more source

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