Formalising Brauer Group and Group Cohomology in Lean4
- 👤 Speaker: Jujian Zhang (Imperial College London)
- 📅 Date & Time: Thursday 20 February 2025, 17:00 - 18:00
- 📍 Venue: MR14 Centre for Mathematical Sciences
Abstract
The concept of Brauer Groups, originally developed to classify division algebras, has now found many uses in scheme theory and class field theory. Brauer Groups over a field k is defined as the collection of central simple algebras over k modulo certain equivalence relations and this project is set out to formalise the correspondence between the Brauer groups and the second Galois cohomology groups Br(k) ≅ H²(Gal(k_sep/k) , k ⃰_sep). In this talk, we give a complete formalisation between the relative Brauer group of a finite dimensional field extension Br(K/k) and the second group cohomology H²(Gal (K/k) , K ⃰) as the first step.
Slides: https://github.com/Whysoserioushah/BrauerGroup_new
Github Repository: https://github.com/Whysoserioushah/BrauerGroup_new
Series This talk is part of the Formalisation of mathematics with interactive theorem provers series.
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Jujian Zhang (Imperial College London)
Thursday 20 February 2025, 17:00-18:00