Let A<sub>l</sub> = [a<sub>ij</sub>(l)] be a strictly upper triangular n×n matrix on C<sup>n</sup> with <sup>a</sup>jj+1<sup>(l)</sup> ≠ 0 for j=1, 2, ..., n -1 and R=⊕<sup>k</sup><sub>i=1</sub> A<sub>i</sub> In this paper, we prove that if S is the double commutants of R, then there are polynomials p<sub>i</sub>… (More)