A Numerical Condition for a Deformation of a Gorenstein Surface Singularity to Admit a Simultaneous Log-canonical Model
نویسنده
چکیده
Let π : X → T be a deformation of a normal Gorenstein surface singularity over the complex number field C. We assume that T is a neighborhood of the origin of C. Then we prove that π admits a simultaneous log-canonical model if and only if an invariant −Pt · Pt of each fiber Xt is constant.
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