English

A^1-connectedness in reductive algebraic groups

Algebraic Geometry 2017-06-05 v3 Group Theory K-Theory and Homology

Abstract

Using sheaves of A^1-connected components, we prove that the Morel-Voevodsky singular construction on a reductive algebraic group fails to be A^1-local if the group does not satisfy suitable isotropy hypotheses. As a consequence, we show the failure of A^1-invariance of torsors for such groups on smooth affine schemes over infinite perfect fields. We also characterize A^1-connected reductive algebraic groups over a field of characteristic 0.

Keywords

Cite

@article{arxiv.1605.04535,
  title  = {A^1-connectedness in reductive algebraic groups},
  author = {Chetan Balwe and Anand Sawant},
  journal= {arXiv preprint arXiv:1605.04535},
  year   = {2017}
}

Comments

19 pages; v3: Minor changes and corrections. Corrected a typographical error in the statement of the main theorem in v2

R2 v1 2026-06-22T14:01:03.990Z