Branching Problems of Unitary Representations,
"Perspectives in Representation Theory" Strategic Workshop and Round Table Discussion (organized by Steffen Koenig, Henning Krause, Peter Littelmann, and Gunter Malle),
Physikzentrum Bad Honnef, Germany, 7-9 July 2006.

The branching problem asks how a given irreducible representation of a group decomposes when restricted to a subgroup.

Making an observation on wild features of branching problems of unitary representations for non-compact subgroups, we address the question of finding a criterion for discreteness of spectrum and finiteness of multiplicities in the irreducible decomposition of the restriction of reductive Lie groups.

Applications to other areas of mathematics such as topology of locally symmetric spaces, and global analysis on indefinite-Riemannian homogeneous spaces will be illustrated.

© Toshiyuki Kobayashi