fact: Definition val_type_termRel := Program.Wf.MR (lexprod lt (fun _ => lt)) (fun p => let '(T, n) := p in (existT (fun _ => nat) n (tsize_flat T))).
imports: Lia Equations(Equations) Coq.Relations.Relation_Operators Coq.Wellfounded.Lexicographic_Product