Abstract
Let G be a connected linear algebraic group over a geometric field k of cohomological dimension 2 of one of the types which were considered by Colliot-Thélène, Gille and Parimala. Basing on their results, we compute the group of classes of R-equivalence G(k /R, the defect of weak approximation A Σ(G), the first Galois cohomology H1 (k, G), and the Tate-Shafarevich kernel III1 (k, G) (for suitable k) in terms of the algebraic fundamental group π1 (G). We prove that the groups G(k)/R and A Σ(G) and the set III1 (k, G) are stably k-birational invariants of G.
Original language | English |
---|---|
Pages (from-to) | 292-339 |
Number of pages | 48 |
Journal | Journal of Algebra |
Volume | 276 |
Issue number | 1 |
DOIs | |
State | Published - 1 Jun 2004 |
Bibliographical note
Funding Information:Keywords: Two-dimensional geometric field; Linear algebraic group; Birational invariants; R-equivalence; Weak approximation; Tate–Shafarevich kernel ✩ This research was supported by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities—Center of Excellence Program and by EU RTN HPRN-CT-2002-00287. * Corresponding author. E-mail addresses: [email protected] (M. Borovoi), [email protected] (B. Kunyavski˘ı), [email protected] (P. Gille). 1 The author was partially supported by the Hermann Minkowski Center for Geometry. 2 The author was partially supported by the Ministry of Absorption (Israel), the Minerva Foundation through the Emmy Noether Research Institute of Mathematics, and INTAS 00-566. 3 The author of the Appendix.
Funding
Keywords: Two-dimensional geometric field; Linear algebraic group; Birational invariants; R-equivalence; Weak approximation; Tate–Shafarevich kernel ✩ This research was supported by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities—Center of Excellence Program and by EU RTN HPRN-CT-2002-00287. * Corresponding author. E-mail addresses: [email protected] (M. Borovoi), [email protected] (B. Kunyavski˘ı), [email protected] (P. Gille). 1 The author was partially supported by the Hermann Minkowski Center for Geometry. 2 The author was partially supported by the Ministry of Absorption (Israel), the Minerva Foundation through the Emmy Noether Research Institute of Mathematics, and INTAS 00-566. 3 The author of the Appendix.
Funders | Funder number |
---|---|
Hermann Minkowski Center for Geometry | |
INTAS | 00-566 |
European Commission | RTN HPRN-CT-2002-00287 |
Minerva Foundation | |
Ministry of Aliyah and Immigrant Absorption | |
Israel Academy of Sciences and Humanities | |
Israel Science Foundation |
Keywords
- Birational invariants
- Linear algebraic group
- R-equivalence
- Tate-Shafarevick kernel
- Two-dimensional geometric field
- Weak approximation