The numerous explicit formulae of the classical theory of quadratic forms revealed remarkable multiplicative properties of the numbers of integral representations of integers by positive definite integral quadratic forms. These properties were explained by the original theory of Hecke operators. As regards the integral representations of quadratic forms in more than one variable by quadratic forms, no multiplicative properties were known at that time, and so there was nothing to explain. However, the idea of Hecke operators was so natural and attractive that soon attempts were made to...

I - Entire functions of several complex variables constitute an important and original chapter in complex analysis. The study is often motivated by certain applications to specific problems in other areas of mathematics: partial differential equations via the Fourier-Laplace transformation and convolution operators, analytic number theory and problems of transcen dence, or approximation theory, just to name a few. What is important for these applications is to find solutions which satisfy certain growth conditions. The specific problem defines inherently a growth scale, and one seeks a...

In the last fifteen years the spectral properties of the Schrodinger equation and of other differential and finite-difference operators with random and almost-periodic coefficients have attracted considerable and ever increasing interest. This is so not only because of the subject's position at the in tersection of operator spectral theory, probability theory and mathematical physics, but also because of its importance to theoretical physics, and par ticularly to the theory of disordered condensed systems. It was the requirements of this theory that motivated the initial study of differential...

Class field theory, which is so immediately compelling in its main assertions, has, ever since its invention, suffered from the fact that its proofs have required a complicated and, by comparison with the results, rather imper- spicuous system of arguments which have tended to jump around all over the place. My earlier presentation of the theory [41] has strengthened me in the belief that a highly elaborate mechanism, such as, for example, cohomol- ogy, might not be adequate for a number-theoretical law admitting a very direct formulation, and that the truth of such a law must be susceptible...

The present volume gives a systematic treatment of potential functions. It takes its origin in two courses, one elementary and one advanced, which the author has given at intervals during the last ten years, and has a two-fold purpose: first, to serve as an introduction for students whose attainments in the Calculus include some knowledge of partial derivatives and multiple and line integrals; and secondly, to provide the reader with the fundamentals of the subject, so that he may proceed immediately to the applications, or to the periodical literature of the day. It is inherent in the nature...

234 Originalvariable x nur ganzzahlige Werte annimmt, dann ist das Integral durch eine unendliche Summe zu ersetzen. Einige der im folgenden behandelten Transformationen gehOren zu diesen beiden Typen. Da wir nUr lineare Transformationen betrachten, wird spiiter die Eigenschaft der Linearitat nicht mehr eigens erwahnt. 2. Der Hilbertsche Raum L2 Bei einer Integraitransformation HiBt man i. aUg. als Original funktionen aUe I (x) zu, fur die das Integral existiert. Manche Eigen schaften der Transformation lassen sich aber nUr dann exakt formu lieren und beweisen, wenn man die I (x) auf engere...

Als Felix Klein den Plan faBte, die wichtigsten seiner autogra phierten Vorlesungen im Druck erscheinen zu lassen, gedachte er, mit der Nichteuklidischen Geometrie zu beginnen und den alten Text zu vor mit Hille eines jiingeren Geometers, des Herro Dr. Rosemann, in der Anlage und den Einzelheiten einer griindlichen Neubearbeitung zu unterziehen. Diese Arbeit erwies sich als langwieriger wie urspriing lich geschatzt. Klein selbst konnte ihren AbschluB nicht mehr erleben. Zwar hatte er in taglichen, durch mehr als ein J ahr fortgesetzten Be sprechungen den Stoff bis in die Einzelheiten hinein...