English

More Examples of Non-Rational Adjoint Groups

Rings and Algebras 2013-07-09 v1 Group Theory

Abstract

We give a recursive construction to produce examples of quadratic forms q_n in the n-th power of the fundamental ideal in the Witt ring whose corresponding adjoint groups PSO(q_n) are not stably rational. Computations of the R-equivalence classes of adjoint classical groups by A.S. Merkurjev are used to show that these groups are not R-trivial. This extends earlier results of A.S. Merkurjev and P.Gille where the forms considered have non-trivial and trivial discriminants respectively.

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Cite

@article{arxiv.1307.2143,
  title  = {More Examples of Non-Rational Adjoint Groups},
  author = {Nivedita Bhaskhar},
  journal= {arXiv preprint arXiv:1307.2143},
  year   = {2013}
}
R2 v1 2026-06-22T00:47:35.330Z