Algebraic Geometry Seminar

Seminar information archive ~02/27Next seminarFuture seminars 02/28~

Date, time & place Friday 13:30 - 15:00 ハイブリッド開催/117Room #ハイブリッド開催/117 (Graduate School of Math. Sci. Bldg.)
Organizer(s) GONGYO Yoshinori, NAKAMURA Yusuke, TANAKA Hiromu

Seminar information archive

2007/06/22

16:30-18:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Qi Zhang (Missouri大学)
Projective varieties with nef anti-canonical divisors
[ Abstract ]
Projective varieties with nef anti-canonical divisors appear naturally in the minimal model program and the theory of classification of higher-dimensional algebraic varieties. In this talk we describe a comprehensive approach to birational geometry of log canonical pair (X, D) with nef anti-canonical class -(K_X+D). In particular, We present two theorems on the birational structure of the varieties. We will also discuss some recent results and new aspects of the subject.

2007/05/15

14:30-16:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Mikhail Kapranov (Yale 大学)
Riemann-Roch for determinantal gerbes and smooth manifolds
[ Abstract ]
A version of the Riemann-Roch theorem for curves due to Deligne, describes the determinant of the cohomology of a vector bundle E on a curve.
If one realizes E via the Krichever construction, the determinant of the cohomology becomes a Hom-space in the determinantal gerbe for the vector space over the field of power series. So one has a ``local" Riemann-Roch problem of description of this gerbe itself. The talk will present the results of a joint work with E. Vasserot describing the class of such a gerbe in a family which geometrically can be seen as a circle fibration. This can be further generalized to the case of a fibration with fibers being smooth compact manifolds of any dimension d (joint work with P. Bressler, B. Tsygan and E. Vasserot).

2007/05/07

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
謝啓鴻(Xie Qihong) (東大・数理)
Pathologies on ruled surfaces in positive characteristic
[ Abstract ]
We discuss some pathologies of log varieties in positive characteristic. Mainly, we show that on ruled surfaces there are counterexamples of several logarithmic type theorems. On the other hand, we also give a characterization of the counterexamples of the Kawamata-Viehweg vanishing theorem on a geometrically ruled surface by means of the Tango invariant of the base curve.

2007/03/26

15:30-17:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Professor Caucher Birkar (University of Cambridge)
Existence of minimal models and flips (3rd talk of three)

2007/03/22

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Professor Caucher Birkar (University of Cambridge)
On boundedness of log Fano varieties (2nd talk of three)

2007/03/20

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Professor Caucher Birkar (University of Cambridge
)
Singularities and termination of flips (1st talk of three)

2007/01/26

16:30-17:30   Room #128 (Graduate School of Math. Sci. Bldg.)
Professor Frans Oort
(Department of Mathematics
University of Utrecht
)
Irreducibility of strata and leaves in the moduli space of
abelian varieties I (a survey of results)

2006/12/08

15:00-16:25   Room #126 (Graduate School of Math. Sci. Bldg.)
Stefan Kebekus 氏 (Mathematisches Institut
Universität zu Köln
)
Rationally connected
foliations

2006/12/04

16:30-18:00   Room #126 (Graduate School of Math. Sci. Bldg.)
Professor Burt Totaro



(University of Cambridge)

When does a curve move on a surface, especially over a finite field?




2006/11/13

16:30-18:00   Room #126 (Graduate School of Math. Sci. Bldg.)
青木昌雄 (京大数理研)
Hom stacks and Picard stacks

2006/10/18

16:00-18:15   Room #122 (Graduate School of Math. Sci. Bldg.)
E. Esteves (IMPA) 16:00-17:00

Jets of singular foliations and applications
to curves and their moduli spaces

F. Zak (Independent Univ. of Moscow) 17:15-18:15
Dual varieties, ramification, and Betti numbers
of projective varieties

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