'Et moi, ... si j'avait su comment en revenir, One service mathematics has rendered the je n'y serais point allC:.' human. race. It has put common sense back Jules Verne where it belongs, on the topmost shelf next to the dusty canister labelled 'discarded non- The series is divergent; therefore we may be sense'. able to do something with it. Eric T. Bell O. Heaviside Mathematics is a tool for thought. A highly necessary tool in a world where both feedback and non linearities abound. Similarly, all kinds of parts of mathematics serve as tools for other parts and for other sciences. Applying a simple rewriting rule to the quote on the right above one finds such statements as: 'One service topology has rendered mathematical physics .. .'; 'One service logic has rendered com puter science .. .'; 'One service category theory has rendered mathematics .. .'. All arguably true. And all statements obtainable this way form part of the raison d'ttre of this series.

Inhalt
one. Sturm-Liouville operators.- 1 Spectral theory in the regular case.- 2 Spectral theory in the singular case.- 3 The study of the spectrum.- 4 The distribution of the eigenvalues.- 5 Sharpening the asymptotic behaviour of the eigenvalues and the trace formulas.- 6 Inverse problems.- two. One-dimensional Dirac operators.- 7 Spectral theory in the regular case.- 8 Spectral theory in the singular case.- 9 The study of the spectrum.- 10 The solution of the Cauchy problem for the nonstationary Dirac system.- 11 The distribution of the eigenvalues.- 12 The inverse problem on the half-line, from the spectral function.- References.- Name Index.