Analytic number theory and part of the spectral theory of operators
(differential, pseudo-differential, elliptic, etc.) are being merged
under amore general analytic theory of regularized products of certain
sequences satisfying a few basic axioms. The most basic examples consist
of the sequence of natural numbers, the sequence of zeros with positive
imaginary part of the Riemann zeta function, and the sequence of
eigenvalues, say of a positive Laplacian on a compact or certain cases
of non-compact manifolds. The resulting theory is applicable to ergodic
theory and dynamical systems; to the zeta and L-functions of number
theory or representation theory and modular forms; to Selberg-like zeta
functions; andto the theory of regularized determinants familiar in
physics and other parts of mathematics. Aside from presenting a
systematic account of widely scattered results, the theory also provides
new results. One part of the theory deals with complex analytic
properties, and another part deals with Fourier analysis. Typical
examples are given. This LNM provides basic results which are and will
be used in further papers, starting with a general formulation of Cram
r's theorem and explicit formulas. The exposition is self-contained
(except for far-reaching examples), requiring only standard knowledge of
analysis.