fact: Definition tower r n U (e : n.-tuple L) (pw : n.-tuple nat) := [forall i : 'I_n, r << U & take i e >>%VS (tnth e i) (tnth pw i)].
imports: HB(structures) mathcomp(all_ssreflect all_fingroup all_algebra) mathcomp(all_solvable all_field polyrcf) Abel(various classic_ext map_gal algR) Abel(char0 cyclotomic_ext real_closed_ext)