ABSTRACT

Chapter 3

Regularization Methods

In the rst two chapters we investigated the Cauchy problem

u

(t) = Au(t); t 0; u(0) = x; (CP)

where A : D(A) X ! X , which is not uniformly well-posed. The

technique of integrated and C-regularized semigroups presented in Chapter

1 allows one to construct a solution of (LCP) for initial values x from

various subsets of D(A) stable in X with respect to x in corresponding

graph-norms. The technique of distributions presented in Chapter 2 allows

the construction of a generalized solution for any x 2 X stable in a space

of distributions.