The cost of dinner will be covered for all out–of–town participants and organizers. The size of the function room at the restaurant is just large enough to seat all registered out–of–town participants. Other local participants who would like to attend the dinner should contact Nancy Rohring and Jason Starr to determine if that is possible (and to discuss the cost of the dinner).
Alcohol is not included. Participants will have to pay for their own alcohol tab.
Saturday |
Event |
Sunday |
Event |
| 8:30AM-9:30AM | Registration and coffee | 8:30AM-9:00AM | Coffee |
| 9:30AM-10:30AM | Arend Bayer, The local projective plane, a fractal curve and Γ1(3) | 9:00AM-10:00AM | Ana–Maria Castravet, Rational curves of minimal degree on higher Fano manifolds |
| 10:30AM-10:45AM | Break | 10:00AM-10:15AM | Break |
| 10:45AM-11:15AM | Pre–lecture | 10:15AM-10:45AM | Pre–lecture |
| 11:15AM-12:15PM | Jenia Tevelev, On the cone of effective divisors of M0,n | 10:45AM-11:45AM | Herb Clemens, Exploring the Hodge problem |
| 12:15PM-1:45PM | Lunch | 11:45AM-12NOON | Break |
| 1:45PM-2:15PM | Pre–lecture | 12NOON-1:00PM | Amanda Knecht, Rationally connected varieties over ℚpnr |
| 2:15PM-3:15PM | Mike Roth, A local-global principle for weak approximation of varieties over function fields | 1PM | Workshop ends |
| 3:15PM-3:45PM | Break |
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| 3:45PM-4:15PM | Pre–lecture |
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| 4:15PM-5:15PM | William Fulton, Character formulas |
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| 7PM-10PM | Dinner (John Harvard's) |
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I will report on joint work with E. Macri on the space of stability conditions for the derived category of the total space of the canonical bundle on the projective plane. It is a 3–dimensional manifold, with many chamber decompositions coming from the behaviour of moduli spaces of stable objects under change of stability conditions.
I will explain how this space is related to classical results by Drezet and Le Potier on stable vector bundles on the projective plane. Using the space helps to determine the group of auto-equivalences, which includes a subgroup isomorphic to Γ1(3). Finally, via mirror symmetry, it contains a universal cover of the moduli space of elliptic curves with Γ1(3)–level structure.
This is joint work with Carolina Araujo. We will discuss a notion of higher Fano variety introduced by de Jong and Starr. We will especially study what one can say about the families of minimal degree rational curves that sweep out such a higher Fano variety. Related questions: Can one classify higher Fanos? Is there an inductive structure on the collection of all higher Fano varieties?
I will give a brief explanation of the Hodge conjecture for complex projective manifolds of even dimension and the use of normal functions in studying it. I will then build on work of Voisin to generalize the notion of normal function in order to create a context for studying the Hodge problem for complex projective manifolds of dimension 2n by induction on n.
In this expository talk, we will give a simple formula, with a simple proof, for the equivariant euler characteristic of an equivariant vector bundle on a complete, smooth variety with an action of a diagonalizable group. On homogeneous varieties this gives Weyl's character formula, and on toric varieties it gives Brion's formula for lattice points in polytopes. This is based on ideas of George Quart in the 1970's and recent conversations with Bill Graham.
A result of Graber, Harris, and Starr shows that a rationally connected variety defined over the function field of a curve over the complex numbers always has a rational point. Similarly, a separably rationally connected variety over a finite field or the function field of a curve over any algebraically closed field has a rational point. We will discuss the case of rationally connected varieties over the maximally unramified extension of the p-adics. They `usually' have points, and we will define what `usually' means.
I will talk on two problems that are related to Hilbert schemes of points. The first is to study the Hilbert schemes of points on a tame Deligne-Mumford stack. I shall talk on smoothness, connectedness and Betti numbers of such Hilbert schemes (joint work with Jason Starr). The second problem is about generators of the diagonal ideal of (ℂ2)n and q,t-Catalan numbers (joint work with Kyungyong Lee).
Brendan Hassett and Yuri Tschinkel introduced the study of the "weak approximation problem" for varieties over function fields, motivated by the analogous question over number fields. The question is whether local sections can be approximated to arbitrarily high order by global sections, and thus fits in to a well known (and fruitful) class of "local-global" type questions. The purpose of this talk is to study whether the weak approximation problem is itself purely local. This is joint work with Jason Starr.
We give a conjectural description of the cone of effective divisors of the Grothendieck-Knudsen moduli space M0,n of stable rational curves. Roughly speaking, non-boundary extremal divisors correspond to total stable degenerations (or, equivalently, pair-of-pants decompositions) with some decorations of smooth curves of genus n-3. Joint with Ana-Maria Castravet.