The space of upper triangular matrices with Hilbert{Schmidt norm can be viewed as a nite dimensional analogue of the Hardy space H2 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.

In this note we prove that every finite collection of connected algebraic subgroups the group triangular automorphisms affine space generates a solvable subgroup.

Coxeter decompositions of hyperbolic simplices where studied in math.MG/0212010 and math.MG/0210067. In this paper we use the methods of these works to classify Coxeter decompositions of bounded convex pyramids and triangular prisms in the hyperbolic space IH.

The application of spectral information to image segmentation is examined, with an approach to colour manipulation being described. A transformation from red/green/blue space to intensity/saturation/hue is advocated, using a triangular polar space to reduce non-linearity. A colour orientated edge detector is described for this space. The methodology is illustrated with two applications, the rea...