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Gorenstein Threefold Singularities with Small Resolutions via Invariant Theory for Weyl Groups

Sheldon Katz·David R. Morrison
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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 by-product, generators of the ring of invariants are given for the standard action of the Weyl group of each of the irreducible root systems.

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BibTeXRIS

Sheldon Katz, David R. Morrison. 1992-02-05. Gorenstein Threefold Singularities with Small Resolutions via Invariant Theory for Weyl Groups. https://arxiv.org/abs/alg-geom/9202002

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