2024/11/10 by Alessandro D'Angelo, D'Angelo, Alessandro
Computer Science · Mathematics · #Algebraic Geometry (math.AG) #Algebraic Topology (math.AT) #Algebraic structures and combinatorial models #Coding theory and cryptography #FOS: Mathematics #Finite Group Theory Research #K-Theory and Homology (math.KT)
paper · pdf · doi:10.48550/arxiv.2411.06504
openalex publication_date 2024/11/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
In this paper we are going to compute the KW -Euler classes for rank 2 vector bundles on the classifying stack BN , where N is the normaliser of the standard torus in SL2 and KW represents Balmer's derived Witt groups. Using these computations we will recover, through a new and different strategy, the formulas previously obtained by Levine in Witt-sheaf cohomology. In order to obtain our results, we will prove Künneth formulas for products of GLn's and SLn's classifying spaces and we will develop from scratch the basic theory of twisted symplectic bundles with their associated twisted Borel classes in SL-oriented theories.