ABSTRACT
Of course, all hypotheles of Theorem 13.2 are satisfied if the functions c, I, m and n are jointly continuous, but not vice versa. The hypotheses of Theorem 13.2 are also satisfied if III(t, 8, .)I/LP S A, < 00, IIm(t,s,·)IILf S Am < 00, IIn(t,8,·,·)IILr S An < 00 (1 < p,q,r < (0), the function c is continuous, and the kernel functions I, m and n are discontinuous only along finitely many surfaces with parameter representation T = ret,s) and (1 = (1(t,s) (KALITVIN-JANKELEVICB [1994]).
