Data: giovedì 7 Aprile 2011, ore 14.00
Luogo: Aula Dal Passo, Dip. Matematica, Univ. Roma "Tor Vergata"
Speaker: Erik Koelink, Radboud Universiteit Nijmegen
Titolo: Matrix-valued spherical functions related to (SU(2)xSU(2), SU(2))
Abstract: To an irreducible (2l+1)-dimensional representation of the group SU(2) we associate spherical functions on SU(2)xSU(2) for each irreducible representation of SU(2)xSU(2). These functions take their values in the (2l+1)x(2l+1)-matrices, and satisfy some useful properties such as orthogonality relations, recurrence relations, eigenfunctions of suitable differential operators, etc. Grouping these functions leads to a new sets of matrix-valued orthogonal polynomials. The one-dimensional case l=0 reduces to the characters on SU(2), which are Chebychev polynomials. This is joint work with Maarten van Pruijssen (Radboud U. Nijmegen) and Pablo Roman (KU Leuven, Belgium, and U. Cordoba, Argentina).