The theory of explicit formulas for regularized products and series
forms a natural continuation of the analytic theory developed in LNM
1564. These explicit formulas can be used to describe the quantitative
behavior of various objects in analytic number theory and spectral
theory. The present book deals with other applications arising from
Gaussian test functions, leading to theta inversion formulas and
corresponding new types of zeta functions which are Gaussian transforms
of theta series rather than Mellin transforms, and satisfy additive
functional equations. Their wide range of applications includes the
spectral theory of a broad class of manifolds and also the theory of
zeta functions in number theory and representation theory. Here the
hyperbolic 3-manifolds are given as a significant example.