
07/04/2021
10:30
Palestrante: Otoniel Nogueira da Silva
https://meet.google.com/jwj-mdza-noy
Responsável: Igor Santos (Este endereço de email está sendo protegido de spambots. Você precisa do JavaScript ativado para vê-lo.)
Resumo:
Consider a surface X in C^n and a generic projection p : X --> T, where T is a neighborhood of 0 in C. We can see X as a family of curves with fibers X_{t} = p^−1(t) (in other words, a deformation of the special fiber X_{0} = p^−1(0)). When t different from 0 is generic, we say that X_{t} = p^−1(t) is a generic fiber of p. We have the following natural question:
Question: How can we compare (in some sense) the singularities of the generic and special fiber?
In general terms, that’s the idea of equisingularity theory, i.e., how to compare the singularities that appear in the family X_{t}. In this talk, we will speak about invariants that control some types of equisingularity of X. When X is not Cohen-Macaulay the special fiber X_{0} has a \fat point" at the origin. So, since X_{0} is no longer reduced, it seems that the classical invariants like the Milnor number cannot be applied directly. Hence, we need new invariants to control the equisingularity of X.