3 Feb 2009: Seminar Michel Jambu

The Algebra Research Group together with Combinatorial Mathematics Research Group Institut Teknologi Bandung will organize two Seminar Matematika on 
 
Tuesday 3rd February 2009 
Time : 11.00.-12.00. 
Place : Mathematics Building ITB 
 
Title : Homotopy Groups of Complements of Complex Hyperplane Arrangements 
 
and 
 
Wednesday 4 February 2009 
Time : 11.00.-12.00. 
Place : Mathematics Building ITB 
 
Title : Witt Formula and Braid Groups 
 
Speaker : Prof. Michel Jambu, Universite de Nice, France 
 
Abstracts: 
 
1. Homotopy Groups of Complements of Complex Hyperplane Arrangements 
 
One of the fundamental problems in topological study of polynomial function f from C^l to C is the computation of the homotopy groups of the complement of the hypersurface V(f). In this talk, we focus on the case where f is a product of degree one polynomial. We will characterize the K(pi,1)-spaces and we give some results about the homotopy for a large class. 
 
2. Witt Formula and Braid Groups 
 
According to a classical result of W.Magnus, the associated graded Lie algebra defined by the lower central series of a group, reflects many properties of the group. We will consider the pure braid groups which will be view as the fundamental group of the complement of a complex algebraic hypersurface. Finally we extend these results to a more general class of complex algebraic hypersurfaces.