Published online by Cambridge University Press: 20 November 2018
Introduction. Let K be an algebraically closed field, G = SL(3, K) the group of 3 × 3 matrices over K of determinant 1. Let denote the monoid of all 3 × 3 matrices over K. If e is an idempotent in
, then
are opposite parabolic subgroups of G in the usual sense [1], [28]. However the map
does not exhaust all pairs of opposite parabolic subgroups of G. Now consider the representation ϕ:G → SL(6, K) given by