Discrepancy of Signed Measures and Polynomial Approximation

Hans-Peter Blatt

ISBN 10: 0387986529 / ISBN 13: 9780387986524

Verlag: Springer New York, Springer US, 2001

Beschreibung

Druck auf Anfrage Neuware - Printed after ordering - In many situations in approximation theory the distribution of points in a given set is of interest. For example, the suitable choiee of interpolation points is essential to obtain satisfactory estimates for the convergence of interpolating polynomials. Zeros of orthogonal polynomials are the nodes for Gauss quadrat ure formulas. Alternation points of the error curve char acterize the best approximating polynomials. In classieal complex analysis an interesting feature is the location of zeros of approximants to an analytie function. In 1918 R. Jentzsch [91] showed that every point of the circle of convergence of apower series is a limit point of zeros of its partial sums. This theorem of Jentzsch was sharpened by Szegö [170] in 1923. He proved that for apower series with finite radius of convergence there is an infinite sequence of partial sums, the zeros of whieh are 'equidistributed' with respect to the angular measure. In 1929 Bernstein [27] stated the following theorem. Let f be a positive continuous function on [-1, 1]; if almost all zeros of the polynomials of best 2 approximation to f (in a weighted L -norm) are outside of an open ellipse c with foci at -1 and 1, then f has a continuous extension that is analytic in c.

Bestandsnummer des Verkäufers 9780387986524

Bibliografische Details

• Titel: Discrepancy of Signed Measures and Polynomial Approximation
• Verlag: Springer New York, Springer US
• Erscheinungsjahr: 2001
• Sprache: Englisch
• ISBN-10: 0387986529
• ISBN-13: 9780387986524
• Einband: Buch
• Zustand: Neu
• Abmessungen: 241B x 160 H x 30 T Millimeter Breite: 241 mm, Höhe: 160 mm, Tiefe: 30 mm
• Gewicht: 852 Gramm

Über diesen Titel

Inhaltsangabe

A concise outline of the basic facts of potential theory and quasiconformal mappings makes this book an ideal introduction for non-experts who want to get an idea of applications of potential theory and geometric function theory in various fields of construction analysis.

Von der hinteren Coverseite

The book is an authoritative and up-to-date introduction to the field of Analysis and Potential Theory dealing with the distribution zeros of classical systems of polynomials such as orthogonal polynomials, Chebyshev, Fekete and Bieberbach polynomials, best or near-best approximating polynomials on compact sets and on the real line. The main feature of the book is the combination of potential theory with conformal invariants, such as module of a family of curves and harmonic measure, to derive discrepancy estimates for signed measures if bounds for their logarithmic potentials or energy integrals are known a priori. Classical results of Jentzsch and Szegö for the zero distribution of partial sums of power series can be recovered and sharpened by new discrepany estimates, as well as distribution results of Erdös and Turn for zeros of polynomials bounded on compact sets in the complex plane.
Vladimir V. Andrievskii is Assistant Professor of Mathematics at Kent State University. Hans-Peter Blatt is Full Professor of Mathematics at Katholische Universität Eichstätt.