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Stable Limits of Log Surfaces and Cohen–Macaulay Singularities

✍ Scribed by Brendan Hassett


Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
103 KB
Volume
242
Category
Article
ISSN
0021-8693

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✦ Synopsis


Given a family of surfaces of general type over a smooth curve, one can apply semistable reduction and the minimal model program to obtain a stable reduction. This is the basis for a geometric compactification for moduli spaces of surfaces of general type, due to Kollár, Shepherd-Barron, and Alexeev. However, this approach hinges on the fact that the resulting stable limit has relatively mild singularities; in particular, it should be Cohen-Macaulay. Unfortunately, the standard formalism does not guarantee that stable limits of families of log surfaces are Cohen-Macaulay.

Here we prove that this is the case.