Article ID Journal Published Year Pages File Type
4589327 Journal of Algebra 2006 18 Pages PDF
Abstract

We obtain an alternative proof of an injectivity result by Beauville for a map from the moduli space of quartic del Pezzo surfaces to the set of conjugacy classes of certain subgroups of the Cremona group. This amounts to showing that a projective configuration of five distinct unordered points on the line can be reconstructed from its five projective four-point subconfigurations. This is done by reduction to a question in the classical invariant theory of the binary quintic, which is solved by computer-assisted methods. More precisely, we show that six specific invariants of degree 24, the construction of which was explained to us by Beauville, generate all invariants whose degree is divisible by 48.

Related Topics
Physical Sciences and Engineering Mathematics Algebra and Number Theory