Submission: 2012, May 14
Let G and G' be absolutely almost simple algebraic groups of types B and C respectively, of rank at least 3, and defined over a number field K. We determine when G and G' have the same isomorphism or isogeny classes of maximal K-tori. This leads to the necessary and sufficient conditions for two Zariski-dense S-arithmetic subgroups of G and G' to be weakly commensurable.
2010 Mathematics Subject Classification: 20G15 (11E57 14L35 20G30)
Keywords and Phrases:
Full text: dvi.gz 67 k, dvi 155 k, ps.gz 1113 k, pdf.gz 304 k, pdf 336 k.