科研之友
微信
新浪微博
Facebook
分享链接
摘要
Let G be a simple simply-connected group scheme over a regular local scheme U. Let epsilon be a principal G-bundle over A(U)(1) trivial away from a subscheme finite over U. We show that epsilon is not necessarily trivial and give some criteria of triviality. To this end, we define affine Grassmannians for group schemes and study their Bruhat decompositions for semi-simple group schemes. We also give examples of principal G-bundles over A(U)(1) with split G such that the bundles are not isomorphic to pullbacks from U.
- 出版日期2016-8
