Divisorial contractions to codimension three orbits

25 Feb 2020 · Samuel Boissière, Enrica Floris ·

Let $G$ be a connected algebraic group. We study $G$-equivariant extremal contractions whose centre is a codimension three $G$-simply connected orbit. In the spirit of an important result by Kawakita in 2001, we prove that those contractions are weighted blow-ups.