Rational curves and rational singularities

Hubert Flenner (1) , Mikhail Zaidenberg (2)

1 Fakultät für Mathematik
2 IF - Institut Fourier

We study rational curves on algebraic varieties, especially on normal affine varieties endowed with a $\C^*$-action. For varieties with an isolated singularity, we show that the presence of sufficiently many rational curves outside the singular point strongly affects the character of the singularity. This provides an explanation of classical results due to H.A. Schwartz and G.H. Halphen on polynomial solutions of the generalized Fermat equation.

Keywords: rational curve; C^*-action; C_+-actions; graded algebra; polynomial curve; rational singularity; affine surface; quotient singularity

Domains: Algebraic Geometry [math.AG]; Commutative Algebra [math.AC]; Complex Variables [math.CV]

Hubert Flenner, Mikhail Zaidenberg. Rational curves and rational singularities. Mathematische Zeitschrift, 2003, 244 (3), pp.549-575. ⟨10.1007/s00209-003-0497-z⟩. ⟨hal-00323545⟩