This paper concerns the existence of curves with low gonality on smooth hypersurfaces of sufficiently large degree. It has been recently proved that if $X subset P^{n+1}$ is a hypersurface of degree $dgeq n+2$, and if $Csubset X$ is an irreducible curve passing through a general point of $X$, then its gonality verifies $ gon(C) geq d-n$, and equality is attained on some special hypersurfaces. We prove that if $X subset P^{n+1}$ is a very general hypersurface of degree $dgeq 2n+2$, the least gonality of an irreducible curve $Csubset X$ passing through a general point of $X$ is $ gon(C) = d-leftlfloor ( sqrt{16n+1}-1)/2 ightfloor $, apart from a series of possible exceptions, where $gon(C)$ may drop by one.
Bastianelli, F., Ciliberto, C., Flamini, F., Supino, P. (2019). Gonality of curves on general hypersufaces. JOURNAL DE MATHÉMATIQUES PURES ET APPLIQUÉES, 125, 94-118 [10.1016/j.matpur.2019.02.016].
Gonality of curves on general hypersufaces
Paola Supino
2019-01-01
Abstract
This paper concerns the existence of curves with low gonality on smooth hypersurfaces of sufficiently large degree. It has been recently proved that if $X subset P^{n+1}$ is a hypersurface of degree $dgeq n+2$, and if $Csubset X$ is an irreducible curve passing through a general point of $X$, then its gonality verifies $ gon(C) geq d-n$, and equality is attained on some special hypersurfaces. We prove that if $X subset P^{n+1}$ is a very general hypersurface of degree $dgeq 2n+2$, the least gonality of an irreducible curve $Csubset X$ passing through a general point of $X$ is $ gon(C) = d-leftlfloor ( sqrt{16n+1}-1)/2 ightfloor $, apart from a series of possible exceptions, where $gon(C)$ may drop by one.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.