fact: Definition encode_unOp (c : unOp) : nat + nat := match c with Opp => inl _ 0%N | Inv => inl _ 1%N | Exp n => inl _ n.+2 | Root n => inr _ n end.
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)