Subnormality of Bergman-like weighted shifts

For a, b, c, d 0 with ad − bc > 0, we consider the unilateral weighted shift S(a,b, c,d) with weights αn := an+b cn+d (n 0). Using Schur product techniques, we prove that S(a,b, c,d) is always subnormal; more generally, we establish that for every p 1, all p-subshifts of S(a,b, c,d) are subnormal. As a consequence, we show that all Bergman-like weighted shifts are subnormal.  2005 Elsevier Inc. All rights reserved