Geometry of Neighborhoods of Minimal Rational Curves

Abstract

This is a survey of recent works on the germ-equivalence problem of minimal rational curves on uniruled projective manifolds. Our main interest is when the associated varieties of minimal rational tangents form an isotrivial family of projective varieties. In this case, there is a natural G-structure on a Zariski-open subset of the underlying uniruled projective manifold, which leads to an interaction of algebraic geometry of minimal rational curves with differential geometry of geometric structures. We also discuss the related question of the formal principle for the germ-equivalence of minimal rational curves.