Partial differential equations constitute an integral part of
mathematics. They lie at the interface of areas as diverse as
differential geometry, functional analysis, or the theory of Lie groups
and have numerous applications in the applied sciences. A wealth of
methods has been devised for their analysis. Over the past decades,
operator algebras in connection with ideas and structures from geometry,
topology, and theoretical physics have contributed a large variety of
particularly useful tools. One typical example is the analysis on
singular configurations, where elliptic equations have been studied
successfully within the framework of operator algebras with symbolic
structures adapted to the geometry of the underlying space. More
recently, these techniques have proven to be useful also for studying
parabolic and hyperbolic equations. Moreover, it turned out that many
seemingly smooth, noncompact situations can be handled with the ideas
from singular analysis. The three papers at the beginning of this volume
highlight this aspect. They deal with parabolic equations, a topic
relevant for many applications. The first article prepares the ground by
presenting a calculus for pseudo differential operators with an
anisotropic analytic parameter. In the subsequent paper, an algebra of
Mellin operators on the infinite space-time cylinder is constructed. It
is shown how timelike infinity can be treated as a conical singularity.