Gorenstein Threefold Singularities with Small Resolutions via Invariant Theory for Weyl Groups
Abstract
We classify simple flops on smooth threefolds, or equivalently, Gorenstein threefold singularities with irreducible small resolution. There are only six families of such singularities, distinguished by Koll{á}r's {\em length} invariant. The method is to apply invariant theory to Pinkham's construction of small resolutions. As a byproduct, generators of the ring of invariants are given for the standard action of the Weyl group of each of the irreducible root systems.
 Publication:

arXiv eprints
 Pub Date:
 February 1992
 arXiv:
 arXiv:alggeom/9202002
 Bibcode:
 1992alg.geom..2002K
 Keywords:

 Mathematics  Algebraic Geometry
 EPrint:
 73 pages, AMSLaTeX v1.1