The primary objective of this monograph is to develop an elementary and
self- contained approach to the mathematical theory of a viscous
incompressible fluid in a domain 0 of the Euclidean space ]Rn,
described by the equations of Navier- Stokes. The book is mainly
directed to students familiar with basic functional analytic tools in
Hilbert and Banach spaces. However, for readers' convenience, in the
first two chapters we collect without proof some fundamental properties
of Sobolev spaces, distributions, operators, etc. Another important
objective is to formulate the theory for a completely general domain O.
In particular, the theory applies to arbitrary unbounded, non-smooth
domains. For this reason, in the nonlinear case, we have to restrict
ourselves to space dimensions n = 2,3 that are also most significant
from the physical point of view. For mathematical generality, we will
develop the lin- earized theory for all n 2 2. Although the
functional-analytic approach developed here is, in principle, known to
specialists, its systematic treatment is not available, and even the
diverse aspects available are spread out in the literature. However, the
literature is very wide, and I did not even try to include a full list
of related papers, also because this could be confusing for the student.
In this regard, I would like to apologize for not quoting all the works
that, directly or indirectly, have inspired this monograph.