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.