Limit linear series for curves of compact type with three irreducible components

Abstract

Our aim in this work is to study exact Osserman limit linear series on curves of compact type X with three irreducible components. This case is quite different from the case of two irreducible components studied by Osserman. For instance, for curves of compact type with two irreducible components, every refined Eisenbud-Harris limit linear series has a unique exact extension. But, for the case of three irreducible components, this property is no longer true. We find a condition characterizing when a given refined Eisenbud-Harris limit linear series has a unique exact extension. To do this, it is necessary to understand how to construct exact extensions. We find a constructive method, which describes how to construct all exact extensions of refined limit linear series. By our method, we get that every refined limit linear series has at least one exact extension.

Keywords:

• Compact type curves
• limit linear series

MATHEMATICS SUBJECT CLASSIFICATION:

• 14H50

Acknowledgements

The author would like to thank Eduardo Esteves for several helpful discussions.

Additional information

Funding

This article was developed while the author was enjoying a posdoc position (PNPD-CAPES) at Federal University of Rio de Janeiro.