fact: Fixpoint bt_depth t := match t with | ∅ => 0 | r⪧s => Nat.max (S ⌞r⌟) ⌞s⌟ end where "⌞ t ⌟" := (bt_depth t).
imports: List Arith Lia Max Wellfounded Setoid Eqdep_dec Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list utils_decidable finite seteq) Undecidability.Shared.Libs.DLW.Vec(pos) Undecidability.Shared.Libs.DLW.Wf(wf_finite wf_chains) Undecidability.FOL.TRAKHTENBROT(notations fol_ops)