Displaying 481 – 500 of 1022

Showing per page

On a gap series of Mark Kac

Katusi Fukuyama (1999)

Colloquium Mathematicae

Mark Kac gave an example of a function f on the unit interval such that f cannot be written as f(t)=g(2t)-g(t) with an integrable function g, but the limiting variance of n - 1 / 2 k = 0 n - 1 f ( 2 k t ) vanishes. It is proved that there is no measurable g such that f(t)=g(2t)-g(t). It is also proved that there is a non-measurable g which satisfies this equality.

On a Szegö's theorem of orthogonal polynomials.

Jesús Sánchez Dehesa (1979)

Revista Matemática Hispanoamericana

It is found that the asymptotical density of zeros of a system of orthogonal polynomials whose weight function belongs to a wide class of distribution functions has the expression ρ(x) = π-1 (1 - x2)-1/2. This result is shown in two completely different ways: (1) from a Szegö theorem and (2) from a Geronimus theorem and a finding recently obtained by the author in a context of Jacobi matrices.

On a Theorem of Ingham.

S. Jaffard, M. Tucsnak, E. Zuazua (1997)

The journal of Fourier analysis and applications [[Elektronische Ressource]]

On | A , δ | k -summability of orthogonal series

Xhevat Z. Krasniqi (2012)

Mathematica Bohemica

In the paper, we prove two theorems on | A , δ | k summability, 1 k 2 , of orthogonal series. Several known and new results are also deduced as corollaries of the main results.

On analytic rapidly decreasing functions of a real variable

Gianfranco Cimmino (1983)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Condizione necessaria e sufficiente affinché una funzione rapidamente decrescente di variabile reale sia uniformemente analitica è che per i suoi coefficienti γ 0 , γ 1 , di Fourier-Hermite riesca γ m = 0 ( e m t ) per t > 0 abbastanza piccolo.

On block recursions, Askey's sieved Jacobi polynomials and two related systems

Bernarda Aldana, Jairo Charris, Oriol Mora-Valbuena (1998)

Colloquium Mathematicae

Two systems of sieved Jacobi polynomials introduced by R. Askey are considered. Their orthogonality measures are determined via the theory of blocks of recurrence relations, circumventing any resort to properties of the Askey-Wilson polynomials. The connection with polynomial mappings is examined. Some naturally related systems are also dealt with and a simple procedure to compute their orthogonality measures is devised which seems to be applicable in many other instances.

Currently displaying 481 – 500 of 1022