ELA, Volume 6, pp. 31-55, March 2000, abstract.

On two--sided interpolation for upper triangular matrices

Daniel Alpay and Vladimir Bolotnikov


The space of upper triangular matrices with Hilbert--Schmidt 
norm can be viewed as a finite dimensional analogue of the 
Hardy space H_2 of the unit disk when one introduces the 
adequate notion of ``point'' evaluation. A bitangential 
interpolation problem in this setting is studied.  The 
description of all solution in terms of Beurling--Lax 
representation is given.