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arXiv · 1612.06726

Nodal surfaces with obstructed deformations

Remke Kloosterman
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Abstract

In this text we show that the deformation space of a nodal surface $X$ of degree $d$ is smooth and of the expected dimension if $d\leq 7$ or $d\geq 8$ and $X$ has at most $4d-5$ nodes. (The case $d\leq 7$ was previously covered by Alexandru Dimca by using different techniques.) For $d\geq 8$ we give explicit examples of nodal surfaces with $4d-4$ nodes, for which the tangent space to the deformation space has larger dimension than expected. We give a short discussion on the shape of the deformation space of surfaces of the form $f_1f_2+f_3^2f_4$, where $f_1$ is a linear form.

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Remke Kloosterman. 2016-12-20. Nodal surfaces with obstructed deformations. https://doi.org/10.1007/s10711-017-0232-2

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