Peter Petrov

Title:
Some theorems of Zariski – van Kampen type

Abstract:
After a brief history of Zariski – van Kampen theorem, the relative 
version of the homotopical variation operator is defined, permitting its 
generalization proposed by Eyral. The main result of this talk is a 
further generalization of the latter, giving at the same time partial 
answer to the conjecture of Chéniot – Eyral.