International Journal of Mathematics and Mathematical Sciences 
Volume 26 (2001), Issue 7, Pages 445-448
doi:10.1155/S0161171201006342

A note on minimal envelopes of Douglas algebras, minimal support sets, and restricted Douglas algebras

Carroll Guillory

 Department of Mathematics, University of Louisiana at Lafayette, Lafayette 70504, LA, USA
Received 9 December 2000

Abstract

We characterize the interpolating Blaschke products of finite type in terms of their support sets. We also give a sufficient condition on the restricted Douglas algebra of a support set that is invariant under the Bourgain map, and its minimal envelope is singly generated.