proposition: Lemma prune_D0 : D0 (prune pcond S0).
proof: Proof. move => C. move/(subP (prune_sub _ _)). rewrite inE. by case/and3P. Qed.
imports: Relations Classical_Pred_Type mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base) CompDecModal.PDL(PDL_def)