Splitting of unstable 2-bundles over the complex projective 6-space

Abstract

We prove that any unstable holomorphic 2-bundle over the complex projective space of complex dimension n at least 6 must split into a direct sum of two holomorphic line bundles. The statement with the weaker dimension condition of n at least 4 has been an open conjecture since 1977. One ingredient in our method uses Mathias Peternell's singular variety version of the Barth-Lefschetz theorem which requires the strong dimension condition of n at least 6.