After it was observed by DE GIORGI and CATTABRIGA [I41 and PICCININI [31] that the heat operator is not surjective on the space of all real-analytic functions on R3, HORMANDER [ 181 characterized the linear partial differential operators with constant coefficients which are surjective on all real-analytic functions on a given convex open subset of RN. On the other hand, CATTABRIGA [Ill, [12], showed that the heat operator is not surjective on the classical Gevrey classes Tcd1(lR3) for 1 < d < 2. Sufficient conditions for the surjectivity of linear partial differential operators with constant coefficients were given by CATTABRIGA [Ill and ZAMPIERI [34], [35], where the latter used methods of HORMANDER [18].In the present paper we characterize the surjectivity of linear partial differential operators with constant coefficients on the non-quasianalytic classes gcw,(IRN) which extend the Gevrey classes ridl(IRN) for d > 1 (see PETZSCHE and VOGT [30] and BRAUN, MEISE and TAYLOR [S]). More precisely, we show that for a complex polynomial P i n N variables the differential operator P(D): &{wl@2N) 4 E {~~( I R~) is surjective if and only if the zero variety V ( P ) : = ( z E C N : P ( -Z ) = 0)of P satisfies the following equivalent Phragmtn-Lindelof conditions:
PL(o):There exist 6 > 0 and A 2 1 such that for each B 2 A and E > 0 there exists C > 0 such that each plurisubharmonic function u on V ( P ) which satisfies u(z) < IIm zI + 6o(z) and u(z) 5 B IIm zI for all z E V also satisfies u(z) I A IIm zI + EO(Z) + C for all z E V .There exist R > 0 and A 2 1 such that for each B 2 A and E > 0 there exists C > 0 such that, for each B E V(P) with 181 2 R, each plurisubharmonic function u on V ( P ) which satisfies u(z) I w(B) and u(z) I B (Im Z( for all z E V ( P ) , )Z -el < o(0) also satisfies u(0) I A /Im 81 + m ( 8 ) + C.
PL,(w):') Research partially supported by Deutsche Forschungsgemeinschaft.
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