Qifeng Li, Rigidity of Wonderful Group Compactifications under Fano Deformations

For a complex connected semisimple linear algebraic group G of adjoint type and of rank n, De Concini and Procesi constructed its wonderful compactification X, which is a smooth Fano variety of Picard number n enjoying many interesting properties. In this talk, we will show that the wonderful compactification X is rigid under Fano deformations. Namely, for any family of smooth Fano varieties over a connected base, if one fiber is isomorphic to X, then so are all other fibers. This answers a question raised by Bien and Brion in their work on the local rigidity of wonderful varieties.