Archived Events

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Universal family for subgroups of an algebraic group [2]

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Talk [3]

Speaker:

Michael Le Barbier

Affiliation:

Inst. Fourier/ St. Marin d'Hères/MPI

Date:

Thu, 2010-02-25 15:00 - 16:00

Location:

MPIM Lecture Hall [4]

Parent event:

MPI-Oberseminar [5]

I describe the construction of a moduli space for the connected subgroups of an algebraic group, and of a universal family. I give a quick illustration of the notion of universal families, trough Grassmann varieties, then discuss in turn the construction of a moduli space and of a universal family, balancing general statements and examples.

Recent progress on the local Langlands conjecture for $G_2$ [6]

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Talk [3]

Speaker:

Marty Weissman

Affiliation:

U of California, Santa Cruz/MPI

Date:

Wed, 2010-02-24 14:15 - 15:15

Location:

MPIM Lecture Hall [4]

Parent event:

Number theory lunch seminar [7]

I will describe recent work, joint with G.

Read more [6]

Stabilization hypothesis and higher braided operads [8]

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Talk [3]

Speaker:

Michael Batanin

Affiliation:

Macquarie U, Sydney/MPI

Date:

Tue, 2010-02-23 15:00 - 16:00

Location:

MPIM Lecture Hall [4]

The stabilization hypothesis of Breen,Baez and Dolan states that k-fold monoidal n-category is "the same" as (k+1)-fold (and therefore $\infty$-fold) monoidal n-category if k is grater or equal to n+2. In the first half of my talk I will explain this hypothesis in an informal manner and I will relate it to the geometry of configuration spaces of k points in $R^n$. In somewhat more technical second half I will introduce n-braided operads and will give a sketch of a proof of a stabilization theorem for n-braided operads.

Read more [8]

Irreducibility of the moduli space $I_n$ of mathematical instanton vector bundles on the projective space $P_3$ for arbitrary odd second Chern class $n$ [9]

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Talk [3]

Speaker:

Alexander S.Tikhomirov

Affiliation:

Yaroslavl St. Pedagogical U

Date:

Tue, 2010-02-23 14:00 - 15:00

Location:

MPIM Lecture Hall [4]

The problem of description of the moduli space $I_n$ of mathematical instanton vector bundles on the projective space $P_3$ has been a challenging problem since 70's. It was conjectured by R.Hartshorne in 1976 that $I_n$ is irreducible for an arbitrary second Chern class $n>0$. This problem has an affirmative solution for small values of $n$, up to $n=5$. Namely, the cases $n=1,2,3,4$ and 5 were settled by Barth (1977), Hartshorne (1978), Ellingsrud-Stromme (1981), Barth (1981) and Coanda-Tikhomirov-Trautmann (2003), respectively.

Read more [9]

Homotopy theory of spaces of representations [10]

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Talk [3]

Speaker:

Alejandro Adem

Affiliation:

U of British Columbia/MPI

Date:

Mon, 2010-02-22 16:30 - 17:30

Location:

MPIM Lecture Hall [4]

Circle actions on certain symplectic manifolds with minimal even Betti numbers [11]

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Talk [3]

Speaker:

Hui Li

Affiliation:

U of Luxembourg /U of Bourgogne/MPI

Date:

Mon, 2010-02-22 15:00 - 16:00

Location:

MPIM Lecture Hall [4]

Suppose that the circle acts on a symplectic manifold in a Hamiltonian fashion. Under certain "minimal'' conditions of the fixed point set of the action, we classify the integral cohomology ring and the Chern classes of the manifold, and we classify the circle action.

Determinantal differential operators: reduction from the big to the small. [12]

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Talk [3]

Speaker:

V. Golyshev

Affiliation:

IITP Moscow/MPI

Date:

Mon, 2010-02-22 13:30 - 14:30

Location:

MPIM Lecture Hall [4]

A numerical test of the generalized Birch and Swinnerton-Dyer conjecture [13]

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Talk [3]

Speaker:

Chad Schoen

Affiliation:

Duke U/MPI

Date:

Mon, 2010-02-22 12:00 - 13:00

Location:

MPIM Lecture Hall [4]

In its crudest form the generalized Birch and Swinnerton-Dyer relates the order of vanishing of an L-function at the center of the critical strip to the rank of a Chow group. This talk describes the conjecture and an attempt to put it to a modest test in the case of motives of the form Sym$^3H^1(E)$, where E is an elliptic curve over Q. This is joint work with Joe Buhler and Jaap Top.

Layer cake and homotopy representations I: formal geometry approach [14]

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Talk [3]

Speaker:

Yaël Frégier

Affiliation:

U of Luxembourg

Date:

Thu, 2010-02-18 15:00 - 16:00

Location:

MPIM Lecture Hall [4]

Parent event:

MPI-Oberseminar [5]

Representations up to homotopy of Lie algebras have attracted recently much attention. On the other hand J. Baez has introduced a way to build a homotopy Lie algebra out of a Lie algebra and an n-cocycle. We show in this work a common framework enabling to generalize both notions (replacing Lie algebras by homotopy Lie algebras) and extend them for other types of algebras (commutative and associative). The main tool is the language of homological vector fields on products of formal manifolds. This is a joint work with John Baez.

Harder's conjecture and ratios of standard L-values [15]

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Talk [3]

Speaker:

Neil Dummigan

Affiliation:

Sheffield

Date:

Wed, 2010-02-17 14:15 - 15:15

Location:

MPIM Lecture Hall [4]

Parent event:

Number theory lunch seminar [7]

I will explain how the Bloch-Kato conjecture leads to the following conclusion: any large prime dividing a critical value of the L-function of a classical Hecke eigenform of level 1, should also divide a certain ratio of critical values for the standard L-function of a related genus 2 (and in general vector-valued) Hecke eigenform F. This can be proved in the scalar-valued case, and there is experimental evidence in the vector-valued case (where the relation between f and F is a congruence of Hecke eigenvalues conjectured by Harder).