fact: Definition p02 : 'S_3 := tperm ord0 (Ordinal (erefl (2 < 3))).
imports: mathcomp(all_ssreflect ssralg ssrnum matrix fingroup perm) Reals Lra mathcomp(mathcomp_extra Rstruct reals) ssrR Reals_ext realType_ext Ranalysis_ext ssr_ext ssralg_ext logb fdist convex