fact: Definition lt_pair (c1 c2 : (nat * type)) : Prop := lexprod nat (fun _ => type) lt (fun _ => lt_type) (sigT_of_prod c1) (sigT_of_prod c2).
imports: mathcomp(ssreflect ssrbool eqtype) Arith List String Lia Program Relations Wellfounded Lexicographic_Product QuickChick(QuickChick) QuickChick.stlc(monad)