1. Let L = a a ( x ) D d b 1 S m ( m > 0 an integer, a = (a1, ..., an), ai 2 0 integers, be a properly elliptic differential operator with real coefficients in Cw(Rn). Let Q c Rn be a bounded domain with a smooth boundary aQ and r a ( n -1)-dimensional, closed, smooth surface, which splits up the domain 9 in two parts Qi and Qa. On the boundary asd we consider a normal system B1, ..., B , of boundary operators with ord Bi = mi 5 2m -1 and smooth coefficients, which fulfils the classical roots condition (see [8], [9], [13]). We consider a fixed set c Qa and define LG(9) as the set of all solutions of the boundary value problem L u = g i n Q , Bj~laa 10 ( j = 1, ..., m ) , where g is an arbitrary function with g Cl(Q) (0 < ii < 1) and g 3 0 in Q \ a. Wm-l(I') denotes the BANAOH space of all WEIITNEY-TAYLOR fields g = (gm)rars,-l on I' with the norm Ilgllwm-~cr, = z SUP I9AX)lIalSrn-1 z U (1.1) Every continuous linear functional 1 on Wm-l(f) can be represented by means of a vector measure (,ua)IaILm-I (supp pa c I') in the form Q ) = z J ga(z) d~a ( x ) IalSm-1 f' (see [91). The mean subject of the present paper is the following Theorem 1. We suppose (i) The homogeneous DIRIUHLET problem of the equation Lu = 0 i n Oi has only the trivial solution. 15 Math. Nachr. Bd. 115