Beitraege zur Algebra und Geometrie
Contributions to Algebra and Geometry
Volume 34 (1993), No. 1, 57-62.

A Criterion for the Ideal of a Projectively Embedded Toric
Surface to be Generated by Quadrics

Robert Jan Koelman

Abstract.

We show that the ideal of a projectively embedded toric surface
is generated by quadrics if and only if the polygon which corresponds
to the embedding has more than three lattice points on its boundary.

MSC 1991: Primary 14J25