Discrepancy of Signed Measures and Polynomial Approximation

Analysis is the branch of mathematics concerned with limits of functions, sequences and series. Potential theory is the study of potential functions. This book is an authoritative and up-to-date introduction to both fields.

Concise outline of basic facts of potential theory and quasiconformal mappings ensures book is appropriate introduction to non-experts who want to get an idea of applications of protential theory and geometric function theory in various fields of construction analysis.

Klappentext
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.

Inhalt
1 Auxiliary Facts.- 2 Zero Distribution of Polynomials.- 3 Discrepancy Theorems via TwoSided Bounds for Potentials.- 4 Discrepancy Theorems via One-Sided Bounds for Potentials.- 5 Discrepancy Theorems via Energy Integrals.- 6 Applications of JentzschSzegö and ErdösTurán Type Theorems.- 7 Applications of Discrepancy Theorems.- 8 Special Topics.- A Conformally Invariant Characteristics of Curve Families.- A.1 Module and Extremal Length of a Curve Family.- A.2 Reduced Module.- B Basics in the Theory of Quasiconformal Mappings.- B.1 Quasiconformal Mappings.- B.2 Quasiconformal Curves and Arcs.- C Constructive Theory of Functions of a Complex Variable.- C.1 Jackson Type Kernels.- C.2 Polynomial Kernels Approximating the Cauchy Kernel.- C.3 Inverse Theorems.- C.4 Polynomial Approximation in Domains with Smooth Boundary.- D Miscellaneous Topics.- D.1 The Regularized Distance.- D.2 Green's Function for a System of Intervals.- Notation.