2026/03/05 by Vikraman Balaji, Yashonidhi Pandey
Mathematics · #math.AG
We prove that split reductive BT group schemes over a higher dimensional base are \em affine. Our method also gives a new construction of higher BT-group schemes more general than parahoric ones. The new ingredients are an extension of J.-K.Yu's construction in \citeyu to higher dimensional bases, Néron-Raynaud dilatations of subgroup schemes on divisors, combined with techniques from \citebt2 and the structure theory developed in \citebp.