Seminar Calendar
for Algebraic Geometry Seminar events the year of Thursday, November 5, 2009.

     .
events for the
events containing  

(Requires a password.)
More information on this calendar program is available.
Questions regarding events or the calendar should be directed to Tori Corkery. 
     October 2009          November 2009          December 2009    
 Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
              1  2  3    1  2  3  4  5  6  7          1  2  3  4  5
  4  5  6  7  8  9 10    8  9 10 11 12 13 14    6  7  8  9 10 11 12
 11 12 13 14 15 16 17   15 16 17 18 19 20 21   13 14 15 16 17 18 19
 18 19 20 21 22 23 24   22 23 24 25 26 27 28   20 21 22 23 24 25 26
 25 26 27 28 29 30 31   29 30                  27 28 29 30 31

Tuesday, January 27, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, January 27, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Arthur B. Coble (Department of Mathematics, University of Illinois)
Organizational meeting
Abstract: We'll meet to discuss speakers for this semester's seminar. We will also discuss a proposal to have a working seminar this semester (on a topic to be decided).

Tuesday, February 17, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, February 17, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
William Haboush (Department of Mathematics, University of Illinois)
The Fundamental Lemma, Part I

Tuesday, February 24, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, February 24, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Bill Haboush (UIUC Math)
The Fundamental Lemma, II
Abstract: This will be the second lecture introducing the Fundamental Lemma (following T. Hales's article).

Tuesday, March 3, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, March 3, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Bill Haboush (University of Illinois)
Statement of the Fundamental Lemma, III
Abstract: This is the third in a series of talks leading up to a precise statement of the Fundamental Lemma (recently proven by Ngo). It is based on the paper of T. Hales, "A statement of the fundamental lemma."

Tuesday, March 10, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, March 10, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Susan Sierra (University of Washington)
Transversality and noncommutative geometry
Abstract: Let Z and Y be closed subvarieties of a variety X. We say that Z and Y are _homologically_transverse_ if the higher Tor's of their structure sheaves all vanish. Now let G be an algebraic group acting on X. We give conditions on Z that ensure that for any Y, the general translate of Z under the action of G is homologically transverse to Y. This result generalizes a recent result of Miller and Speyer for transitive group actions and ultimately goes back to the classical Kleiman-Bertini theorem. We give applications to noncommutative algebraic geometry, including the classification of noncommutative surfaces.

Tuesday, March 17, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, March 17, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Donghoon Hyeon (Marshall University)
A new look at the moduli space of hyperelliptic curves
Abstract: There are two natural ways to compactify the moduli space of smooth hyperelliptic curves of genus g: one is to take the closure in the moduli space of stable curves of genus g, and the other is to construct the GIT quotient of semistable binary forms of degree 2g + 2. Avritzer and Lange showed that there is a projective birational morphism f from the former to the latter extending the natural isomorphism between the loci of smooth curves. By carrying out a log minimal model program, we prove that f decomposes into a series of divisorial contractions collapsing the boundary divisors in natural order. We also obtain a conjectural formula for critical values in the log MMP for the moduli of stable hyperelliptic curves which are also expected to be critical values for the log MMP for the moduli of stable curves. They are then identified with the values from a formula obtained by considering the GIT stability of curves. This suggests that log canonical models can be constructed as GIT quotients of Hilbert scheme of curves that are 'rationally' semistable.

Thursday, March 19, 2009

Special Algebraic Geometry Seminar
1:00 pm   in 243 Altgeld Hall,  Thursday, March 19, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Bill Haboush (UIUC Math)
The statement of the fundamental lemma
Abstract: This continues our series on the statement of the Fundamental Lemma, recently proven by Ngo.

Tuesday, March 31, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, March 31, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Davesh Maulik (MIT)
Gromov-Witten Theory of K3 Surfaces

Tuesday, April 14, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, April 14, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Elizabeth Csima (UIUC)
The reduction of the fundamental lemma to the Lie algebra case

Tuesday, August 25, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, August 25, 2009
 Del 
 Edit 
 Copy 
Submitted by katzs.
Sheldon Katz   [email] (UIUC Math)
A classical perspective of algebraic geometry
Abstract: This is an expository talk, designed to be accessible to graduate students with little or no prior exposure to algebraic geometry.

Tuesday, September 1, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, September 1, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Rahul Pandharipande (Princeton University)
Quivers, curves, and the tropical vertex group
Abstract: Elements of the tropical vertex group are formal families of symplectomorphisms of the 2-dimensional algebraic torus. I will talk about commutators in the tropical vertex group and their relationship to quivers and curve counts. The latter is joint work with Gross and Siebert.

Wednesday, September 2, 2009

Algebraic Geometry Seminar
4:00 pm   in 343 Altgeld Hall,  Wednesday, September 2, 2009
 Del 
 Edit 
 Copy 
Submitted by nevins.
Kevin McGerty (Imperial College)
Rational Cherednik algebras and microlocal versions of the KZ functor
Abstract: We show how the relation of the rational Cherednik algebra in type A with the Hilbert scheme of points in the plane allows one to construct a family of exact functors which generalize the KZ functor of Ginzburg-Guay-Opdam-Rouquier.

Thursday, September 10, 2009

Algebraic Geometry Seminar
3:00 pm   in 241 Altgeld Hall,  Thursday, September 10, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Pierrette Cassou-Nogučs (Université Bordeaux I)
On polynomial maps
Abstract: I will give a survey on polynomial maps from \mathbb{C}^2 to \mathbb{C} and to \mathbb{C}^2 and discuss some questions about those maps.

Tuesday, September 15, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, September 15, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Benjamin Howard (University of Michigan)
The relations among invariants of points on the projective line
Abstract: We consider the coordinate rings of GIT quotients of n points on the projective line modulo automorphisms of the line. In particular we wish to describe such rings by generators and relations. Kempe found generators in 1894. We describe the full ideal of relations in these generators. (This is joint work with John Millson, Andrew Snowden, and Ravi Vakil.)

Tuesday, September 22, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, September 22, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Christian Schnell (University of Illinois at Chicago)
Complex analytic Neron models
Abstract: I will present a global construction of the Neron model for degenerating families of intermediate Jacobians; a classical case would be families of abelian varieties. The construction is based on Saito's theory of mixed Hodge modules; a nice feature is that it works in any dimension, and does not require normal crossing or unipotent monodromy assumptions. As a corollary, we obtain a new proof for the theorem of Brosnan-Pearlstein and Saito that, on an algebraic variety, the zero locus of an admissible normal function without singularities is an algebraic subvariety.

Tuesday, October 6, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, October 6, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Li Li (University of Illinois)
Hilbert schemes of points on a Deligne-Mumford stack
Abstract: I will first review the definition and properties of Hilbert schemes of points on a Deligne-Mumford stack, then talk about how are our Hilbert schemes related to quiver varieties and multigraded Hilbert schemes.

Tuesday, October 13, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, October 13, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Wenchuan Hu (Institute of Advanced Study)
Topological aspects on Chow varieties
Abstract: The topological invariants of Chow varieties can be calculated by the homotopy theoretic method. In this talk I will discuss this method in calculating the Euler Characteristic of Chow varieties. This result has been obtained by Blaine Lawson and Stephen Yau by using a fixed point formula with a torus action. Our calculation in a direct and simple way. This technique also can be generalized to Chow varieties with certain group actions and other cases. Furthermore, I will also talk about the application of the method on l-adic Euler-Poincare Characteristic of Chow varieties over arbitrary algebraic closed field.

Tuesday, October 20, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, October 20, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Henry Schenck (University of Illinois)
On the equivariant Chow cohomology of nonsimplicial toric varieties
Abstract: For a toric variety X determined by a polyhedral fan P in a lattice N, the (rational) equivariant Chow cohomology is a graded Sym(N) module. We study the Chern classes of the associated reflexive sheaf on Proj(N). The first two Chern classes depend only on the combinatorics of P, but c_3 depends on the geometry of codimension two intersections of facets of P.

Tuesday, October 27, 2009

Algebraic Geometry Seminar joint with Algebra,Geometry and Combinatorics Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, October 27, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Matthew Satriano (University of California, Berkeley)
Stacky Resolutions of Singular Schemes
Abstract: Given a singular scheme X, one way to study it is through a resolution of singularities, which is oftentimes hard to control. In certain cases, however, one can construct a smooth stack which well-approximates X and can serve as a replacement for the resolution of singularities. In this talk, I describe two cases where such a stack exists and give applications to Invariant Theory, Hodge Theory, and toric Artin stacks.

Tuesday, November 3, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, November 3, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Bruce Reznick (Department of Mathematics, University of Illinois)
Higher Laws of Inertia
Abstract: Newton's Law of Inertia says that if a real quadratic form is written as a linear combination of the squares of real linear forms, then there are computable lower bounds on the numbers of positive and negative coefficients. It seems natural to wonder what happens in higher (even) degree. It turns out that a similar law applies for binary forms in degree 4, but fails in degree 6 (and probably higher).

Tuesday, November 10, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, November 10, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Pramod N. Achar (Louisiana State University)
Positivity, coherent sheaves, and representation theory
Abstract: A number of questions in representation theory involve an endomorphism algebra endowed with a natural Z-grading; sometimes, deep consequences follow if it can be shown that the negative-degree components vanish. I will explain several instances of such "positivity phenomena" in derived categories of coherent sheaves, following work of Arkhipov, Bezrukavnikov, Ginzburg, and others. I will then discuss a new approach to proving positivity theorems, followed by some potential applications.

Tuesday, November 17, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, November 17, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Steven Bradlow (University of Illinois)
Sp(4,R)-Higgs bundles: a Higgs bundle case study
Abstract: Using G=Sp(4,R) as a special case, we will describe what G-Higgs bundles are and how they can be used to study maps from surface groups into non-compact real Lie groups.

Tuesday, December 1, 2009

Algebraic Geometry Seminar
3:00 pm   in 243 Altgeld Hall,  Tuesday, December 1, 2009
 Del 
 Edit 
 Copy 
Submitted by llpku.
Michael Broshi (University of Notre Dame)
G-Bundles over curves
Abstract: Let X be a Dedekind scheme and G a flat affine group scheme of finite type on X. We give a description of G-bundles on schemes over X inspired by Chevalley's theorem for algebraic groups over a field. As an application, we show that the fibred category of G-bundles over a smooth proper curve over a field is an Artin stack.