Lecture 8 - Aug 31, 2023

Title: Lectures on SGA3
Abstract:
SGA3 was a seminar on group schemes, but it was an ideal test-ground and playground for many of the theories introduced by Grothendieck at that time: faithfully flat descent, sheaves for fpqc, fppf or etale topology, reductions to the noetherian case, infinitesimal and formal methods. All this is rather intimidating when presented in its own right. On the contrary, we intend to present a leisurely introduction, introducing concepts step by step only as needs arise for the study of reductive group schemes (and first of all, tori) and illustrating them by concrete examples. The idea is to share the joy the lecturer had by reading SGA3.