**
Welcome to the Einstein Institute of Mathematics**

Home | About | Staff | Studies | Colloquia & Events | Research | Services & Resources | Sites |

There will be six lectures, each lasting for 45-50 minutes, followed by a few minutes for discussion. The talks will be held at lecture hall 2 of the department of mathematics (Manchester Building).

The symposium will end with a reception for all the participants.

For more information please contact Prof. Avinoam Mann,
email: *mann at vms.huji.ac.il*

**Programme**:

9:30 - Gathering

10:00 - **A. Wigderson:
Expander graphs - where combinatorics and algebra
compete and cooperate**. Abstract

11:00 - Coffee break.

11:30 - **
A. Juhasz:
On some two-relator groups with solvable word and conjugacy
problems**.

12:30 - **
A. Joseph: The injectivity of the Conze embedding**.
Abstract

13:30 - Lunch break (lunch at Beit Belgia will be free of charge).

15:00 - **
M. Larsen: Irrational motivic zeta functions**.

16:00 - **
P. Scott: Splittings of groups and manifolds**.
Abstract

17:00 - Coffee break.

17:30 - **R. Adin:
A unified construction of Weyl group representations**
(Joint work with

18:30 - Reception at the faculty lounge.

**Everybody is welcome!**

**Here are abstracts for some of the talks**:

*A. Wigderson*: Expander graphs - where Combinatorics and Algebra compete and cooperate- Expansion of graphs can be given equivalent definitions in combinatorial and algebraic terms. This is the most basic connection between combinatorics and algebra illuminated by expanders and the quest to construct them. The talk will survey how fertile this connection has been to both fields, focusing on recent results.
*A. Joseph*: The injectivity of the Conze embedding- The Conze embedding defines a homomorphism of the enveloping algebra U(g) of a semisimple Lie algebra g into the algebra A of polynomial valued differential operators on the open Bruhat cell defined relative to a parabolic subalgebra. Moreover A admits a natural filtration defined by the degree of the polynomials. It is shown that gr A is an injective g module in an appropriate category. This determines multiplicities in each filtration step of the image of U(g), which in turn has significant applications to the calculation of the Parthasarathy-Ranga Rao-Varadarajan determinants and to the study of the Brylinski-Kostant filtration defined on simple finite dimensional U(g) modules.
*P. Scott*: Splittings of groups and manifolds- This talk will be a survey of that part of group theory which is to do with understanding amalgamated free products of groups. This area has strong connections with topology. The subject started with the realisation by Hopf that the topological idea of the number of ends of a space could be used to define the number of ends of a group. The first big result was Stallings' structure theorem for groups with more than one end. Interestingly, Stallings says that his result and the arguments were motivated by results in 3-dimensional topology. Since then the subject has developed a great deal, and the connections between topology and group theory have become even stronger.

Back to the Math home page

Mathematics and Computer Science Library | Faculty of Science | The Hebrew University of Jerusalem |

Background image © copyright 1997 by Xah Lee, used with permission.