English

The Rost invariant has trivial kernel for quasi-split groups of low rank

Group Theory 2007-05-23 v2 Rings and Algebras

Abstract

For G an almost simple simply connected algebraic group defined over a field F, Rost has shown that there exists a canonical map R_G: H^1(F, G) --> H^3(F, Q/Z(2)). This includes the Arason invariant for quadratic forms and Rost's mod 3 invariant for Albert algebras as special cases. We show that R_G has trivial kernel if G is quasi-split of type E_6 or E_7. A case-by-case analysis shows that it has trivial kernel whenever G is quasi-split of low rank.

Keywords

Cite

@article{arxiv.math/0009162,
  title  = {The Rost invariant has trivial kernel for quasi-split groups of low rank},
  author = {R. Skip Garibaldi},
  journal= {arXiv preprint arXiv:math/0009162},
  year   = {2007}
}

Comments

Author-supplied DVI/PS files available at http://www.math.ucla.edu/~skip/preprints.html Minor changes since first edition