University of Toronto's Symplectic Geometry Seminar

Monday, 15 June 2009, 2:10pm
HU 1018


Cornell University

Maximal rank subgroups, weight varieties and homogeneous spin-c structures


In this talk I will present a miscellany of facts, some old and some new, concerning the maximal rank subgroups of a compact Lie group. These subgroups were classified long ago by Borel and de Siebenthal. They show up in the singularities of weight varieties, the index theory of homogeneous differential operators, and various induction maps among representation rings. Part of this is ongoing joint work with Megumi Harada and Gregory Landweber.