Quintic threefolds with triple points

Abstract

We study the geometry of quintic threefolds $X\subset {\mathbb{P}}^4$ with only ordinary triple points as singularities. In particular, we show that if a quintic threefold $X$ has a reducible hyperplane section then $X$ has at most $10$ ordinary triple points, and that this bound is sharp. We construct various examples of quintic threefolds with triple points and discuss their defect.

References in corpus (1)

• Counting Lines on Quartic Surfaces