Böcker av Rupert Lasser

The book aims at giving a monographic presentation of the abstract harmonic analysis of hypergroups, while combining it with applied topics of spectral analysis, approximation by orthogonal expansions and stochastic sequences. Hypergroups are locally compact Hausdorff spaces equipped with a convolution, an involution and a unit element. Related algebraic structures had already been studied by Frobenius around 1900. Their axiomatic characterisation in harmonic analysis was later developed in the 1970s. Hypergoups naturally emerge in seemingly different application areas as time series analysis, probability theory and theoretical physics.The book presents harmonic analysis on commutative and polynomial hypergroups as well as weakly stationary random fields and sequences thereon. For polynomial hypergroups also difference equations and stationary sequences are considered. At greater extent than in the existing literature, the book compiles a rather comprehensive list of hypergroups, in particular of polynomial hypergroups. With an eye on readers at advanced undergraduate and graduate level, the proofs are generally worked out in careful detail. The bibliography is extensive.

¿¿Dieses Buch ist entstanden aus Vorlesungen an der Technischen  Universität München und behandelt im Wesentlichen die Themen, die  üblicherweise Gegenstand der Vorlesungen "Analysis" der ersten  beiden Semester im Bachelor-Studium der Mathematik und Physik  sind. Dazu zählen neben den grundlegenden Bausteinen der  eindimensionalen Analysis, wie Konvergenz, Stetigkeit,   Differentiation, Integration, auch eine Einführung in die  Differenzierbarkeit im Mehrdimensionalen, der Begriff der  Konvergenz in metrischen Räumen sowie elementare   Lösungsmethoden von gewöhnlichen Differentialgleichungen. Das Buch zeichnet sich aus durch zahlreiche motivierende Beispiele,  ohne dass dabei die nötige mathematische Präzision zu kurz kommt.  Es eignet sich hervorragend sowohl als Nachschlagewerk als auch als  Begleitlektüre zur Vorlesung.

Addresses various topics in Fourier series, emphasizing the concept of approximate identities and presenting applications, particularly in time series analysis. This title stresses in the idea of homogenous Banach spaces and provides results. It utilizes techniques from functional analysis and measure theory.