– Europe/Lisbon
Room P3.10, Mathematics Building — Online
A gentle introduction to the resolution of singularities of algebraic varieties
The proof for the resolution of singularities in characteristic $0$ is built on a complicated induction frame, doing one main job: it allows one to define at each stage of the resolution process and at each singular point of the current variety a local invariant $\operatorname{inv}_a(X) $ — a string of natural integers $(n_1,n_2,...,n_k)$, considered lexicographically.
This invariant, in turn, performs two jobs:
- It defines the center of the blowups to which the singularities are submitted as the locus of points where the invariant assumes its maximal value.
- It drops after each blowup at the points which have been modified by the blowup.
As the lexicographic order is a well ordering, one arrives in finitely many steps at the minimal value of the invariant, corresponding to a smooth variety.
In the talk, which is for a general audience, we will explain the main ideas of how to construct the invariant. There are some basic principles to observe, and putting these together, everything then evolves quite systematically.