On the McKay correspondences for the Hilbert scheme of points on the affine plane

The quotient of a finite-dimensional vector space by the action of a finite subgroup of automorphisms is usually a singular variety. Under appropriate assumptions, the McKay correspondence relates the geometry of nice resolutions of singularities and the representations of the group. For the Hilbert scheme of points on the affine plane, we study how different correspondences (McKay, dual McKay and multiplicative McKay) are related to each other.     

The quantum differential equation of the Hilbert scheme of points in the plane

We discuss here basic properties of the quantum differential equation of the Hilbert scheme of points in the plane. Our emphasis is on intertwining operators (which shift equivariant parameters) and their applications. In particular, we obtain an exact solution to the connection problem from the Donaldson-Thomas point q = 0 to the Gromov-Witten point q = -1.     

Vanishing theorems and character formulas for the Hilbert scheme of points in the plane

In an earlier paper [14], we showed that the Hilbert scheme of points in the plane H _n =Hilb ⁿ (ℂ²) can be identified with the Hilbert scheme of regular orbits ℂ^{2 n} //S _n . Using this result, together with a recent theorem of Bridgeland, King and Reid [4] on the generalized McKay correspondence, we prove vanishing theorems for tensor powers of tautological bundles on the Hilbert scheme. We apply the vanishing theorems to establish (among other things) the character formula for diagonal harmonics conjectured by Garsia and the author in [9]. In particular we prove that the dimension of the space of diagonal harmonics is equal to (n+1) ^{n -1}. Oblatum 24-V-2001 & 31-I-2002?Published online: 29 April 2002     

Higher codimension cycles on the Hilbert scheme of three points on the projective plane

In this paper, we study the higher codimensional cycle structure of the Hilbert scheme of three points in the projective plane. In particular, we compute all Chern/Segre classes of all tautological bundles on it and compute the nef (effective) cones of cycles in codimensions 2 and 3 (dimensions 2 and 3).     

The Hilbert scheme of points for supersingular abelian surfaces

We study the geometry of Hilbert schemes of points on abelian surfaces and Beauville’s generalized Kummer varieties in positive characteristics. The main result is that, in characteristic two, the addition map from the Hilbert scheme of two points to the abelian surface is a quasifibration such that all fibers are nonsmooth. In particular, the corresponding generalized Kummer surface is nonsmooth, and minimally elliptic singularities occur in the supersingular case. We unravel the structure of the singularities in dependence of p-rank and a-number of the abelian surface. To do so, we establish a McKay Correspondence for Artin’s wild involutions on surfaces. Along the line, we find examples of canonical singularities that are not rational singularities.     

On the reducibility of the postulation Hilbert scheme

We give a condition in terms of the possible graded Betti numbers compatible with a given Hilbert functionH of 0-dimensional subschemes of ℙ ⁿ which implies the reducibility of the postulation Hilbert scheme and of its subscheme which parametrizes reduced subschemes with Hilbert functionH.     

On the Hilbert scheme of curves in higher-dimensional projective space

In this paper we prove that, for anyn≥3, there exist infinitely manyr∈N and for each of them a smooth, connected curveC _r in ℙ ^r such thatC _r lies on exactlyn irreducible components of the Hilbert scheme Hilb(ℙ ^r ). This is proven by reducing the problem to an analogous statement for the moduli of surfaces of general type.     

On the irreducibility of the Hilbert scheme of space curves

Denote by the Hilbert scheme parametrizing smooth irreducible complex curves of degree and genus embedded in . In 1921 Severi claimed that is irreducible if . As it has turned out in recent years, the conjecture is true for and , while for it is incorrect. We prove that , and are irreducible, provided that , and , correspondingly. This augments the results obtained previously by Ein (1986), (1987) and by Keem and Kim (1992).

     

On the number of primitive lattice points in plane domains

We discuss the error term in the asymptotic formula for the number of integral points with coprime coordinates in star like plane domains assuming the validity of the Riemann Hypothesis.