Algebraic Geometry Seminar

Fall 2001

• Thursday, August 2, 2001. 10:30, Burnside 920.

Speaker: Jeff Achter (Columbia)
Title: Differential Galois Theory and Abelian Varieties.

• Wednesday, January 23, 14:00-15:15, Burnside 1205

Speaker: S. Venereau (McGill)
Title: Is any regular embedding of C^k into C^n linearisable?
 
• Wednesday, March 6, 14:00-15:15, Burnside 1205

Speaker: C. Ingalls (U. New Brunswick)
Title: Birational Classification of Orders over Surfaces
Abstract:  We apply Mori's minimal model program for
log surfaces to obtain a birational classification of orders
over surfaces.  This is related to the problem of
classifying division algebras or Brauer-Severi varieties
such as conic bundles.  We will also discuss some
constructions of orders of negative Kodaira dimension.
 
• Wednesday, March 13, 14:00-16:00, Burnside 1205

Speaker: V. Poppov (Steklov Inst.)
Title: *Self-dual algebraic varieties and nilpotent orbit   at  2:00 pm
        *Automorphism groups of finite dimensional simple algebras  at 3:00 pm
 
• Wednesday, March 20, 14:00-16:00, Burnside 1205

Speaker: V. Poppov (Steklov Inst.)
Title: *Generators and relations of affine coordinate rings of semisimple groups  at 2:00 pm
        *Discrete complex reflection groups  at 3:00 pm

• Wednesday, May 1, 13:30-14:30, Burnside 1205

Speaker: V. Brinzanescu (Bucharest/MPI Bonn)
Title:  Holomorphic vector bundles on non-Kaehler elliptic surfaces
• Wednesday, May 1, 15:00-16:00, Burnside 1205

Speaker: K. Khuri-Makdisi (American U. of Beirut)
Title: Linear algebra algorithms for divisors on an algebraic curve

Schedule for 2000-2001
Fall, Winter.

Fall 2000

• Wednesday, September 6, 2000.

Speaker: Lucy Moser-Jauslin (Dijon),
Title: A non linearizable action of S₃ on C⁴.
 
• Thursday, September 14, 2000.     15:00, Burnside 920.         <--- Note the unusual day, time and place.

Speaker:  Nicole Lemire (U. Oregon),
Title: Multiplicative invariant fields and algebraic group invariants.
 
• Wednesday, September 20, 2000.

Speaker:  Karlheinz Kiyek (U. Padeborn),
Title: General elements for complete ideals in
two dimensional  regular local rings and applications.

• Wednesday, September 27.

Speaker: Irene Bouw (U.Penn.),
Title: Hurwitz spaces in mixed characteristic.
 
• Wednesday, November 8.

Speaker: R. Jardin (Western Ontario),
Title: Homotopy theory and algebraic geometry.
 
• Friday, November 10, 14:30-15:30.

Speaker: M. Lahyane (ICTP Trieste)
Title: About exceptional curves in rational surfaces.
 
• Wednesday, November 15.

Speaker: J. Wlodarczyk (Purdue),
Title: Algebraic Morse Theory and Factorization of Birational Maps.
 
• Wednesday, December 6.

Speaker: J. Achter (Columbia),
Title: Monodromy in families of abelian varieties.
 
• Thursday, December 7.

Speaker: T. Asanuma (Toyama),
Title: Multiconnectedness and the Jacobian Conjecture.

La fonction zéta topologique a été introduite par Denef et Loeser. On commencera par rappeller sa définition et les conjectures que Denef et Loeser ont faites à son propos. Après une discussion sur l'état de ces conjectures, on donnera des indications sur des résultats obtenus par Artal, Luengo, Melle et moi-même, à savoir : La fonction zéta topologique n'est pas un invariant topologique, la conjecturede la monodromie est vraie pour les singularités de surfaces superisolées.

This is a report on a work in progress with F. Andreatta. Hilbert modular varieties associated to a totally real field L are singular in characteristic p, if p is ramified in the field L. We define a stratification that refines the Deligne-Pappas singularity strata and determine its properties. This allows us to determine the structure of Newton strata and their dimensions. This new result is one of a few examples where this is known.

Fall 1999

• Wednesday, September 29, 1999 :

Speaker: M. Koras (Warsaw),
Title: Contractible affine surfaces with a quotient singularity
• Wednesday, October 6, 1999 :

Speaker: B. Singh (Tata),
Title:Subintegrality and invertible modules.
• Wednesday, October 20, 1999 :

Speaker: A. Hundemer (McGill),
Title: Comparing the Zariski and Classical topologies: All you always knew and were afraid to ask.
• Wednesday, October 27, 1999 :

Speaker: A. Hundemer (McGill),
Title: Comparing the Zariski and Classical topologies: All you always knew and were afraid to ask (PART II).
• Wednesday, November 17, 1999 :

Speaker: H. Farkas (Hebrew U.),
Title: Some geometry related to the modular group SL(2, Z).
• Tuesday, December 14, 1999 :

Speaker: V. Ostrik (Harvard & Moscow),
Title: A basis in equivariant K-theory of the nilpotent cone.

Winter 2000

• Wednesday, March 1, 2000 :

Speaker: E. Goren (McGill),
Title: Picard groups of moduli problems. Part I: Grothendieck Topologies.
• Wednesday, March 8, 2000 :

Speaker: B. Broer (U de M),
Title: Picard groups of moduli problems. Part II: Etale, smooth and flat maps.
• Wednesday, March 22, 2000 :

Speaker: P. Russell (McGill),
Title: Picard groups of moduli problems. Part III: Moduli Topologies.
• Wednesday, March 29, 2000 :

Speaker: P. Russell and E. Goren (McGill),
Title: Picard groups of moduli problems. Part IV: Moduli Topologies (and versal families).
• Wednesday, April 5, 2000 :

Speaker: E. Goren (McGill),
Title: Picard groups of moduli problems. Part V: Versal Deformations; The Elliptic Topology.
• Wednesday, April 12, 2000 :

Speaker: E. Goren (McGill),
Title: Picard groups of moduli problems. Part VI: The Elliptic Topology.
• Wednesday, April 26, 2000 :

Speakers: The Participants,
Title: Picard groups of moduli problems. Part VII: Conclusion and Discussion.