Date: Wednesday, September 29, 2021
Location: 4096 East Hall (4:00 PM to 5:30 PM)
Title: Rational singularities of nested Hilbert schemes
Abstract: For a smooth surface S, the Hilbert scheme of points S^(n) is a well studied smooth parameter space. In this talk I will consider a natural generalization, the nested Hilbert scheme of points S^(n,m) which parameterizes pairs of 0dimensional subschemes X \supseteq Y of S with deg(X) = n and deg(Y) = m. In contrast to the usual Hilbert scheme of points, S^(n,m) is almost always singular and it is known that S(n,1) has rational singularities. I will discuss some general techniques to study S^(n,m) and apply them to show that S^(n,2) also has rational singularities. This relies on a connection between S^(n,2) and a certain variety of matrices, and involves squarefree GrÃ¶bner degenerations as well as the KempfWeyman geometric technique. This is joint work with Alessio Sammartano.
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Speaker: Ritvik Ramkumar
Institution: UC Berkeley
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