Faithful representations of SL(2) over truncated Witt vectors
arXiv:math/0109107 · doi:10.1016/S0021-8693(03)00269-2
Abstract
Let G be the six dimensional linear algebraic k-group SL_2(W_2), where W_2 is the ring of Witt vectors of length two over the algebraically closed field k of characteristic p>2. Then the minimal dimension of a faithful rational k-representation of G is p+3.
New title. New section 9 contains a finite group version of the main result. 11 pages, AMS LaTeX. To appear in the Journal of Algebra