摘要

We study birational geometry of Fano varieties realized as double covers sigma: V -> P(M), M >= 5, branched over generic smooth hypersurfaces W = W(2(M-1)) of degree 2(M-1). We prove that the only structures of a rationally connected fibre space on V are pencil-subsystems of the free linear system vertical bar-1/2K(v)vertical bar. The groups of birational and biregular self-maps of V coincide: Bir V = Aut V.

  • 出版日期2010-10