ABSTRACT
The space E r = {y e L° : |;c(a>);y(ct>)| dfi < -foo for all x e E) with the norm || • He ' :
is called the Kothe dual space. It is known that supp E f = Q (see [1, Theorem 6.1.3]). A Banach function space E is called perfect (=o-reflexive) if E" = E . Let Y be a subspace of Banach space X . A continuous operator T : Y* -+ X* is
called the norm-preserving extension operator if
The base for an application of main Theorem 1.1 is the following result by G. Lozanovski and M. Braverman (see [2]).
