MAYBE
*** Computating Strongly Quasi-Reducible Parts ***
TRS:
   [ ordered(nil) -> true,
     ordered(cons(?x,?ys)) -> and(leList(?x,?ys),ordered(?ys)),
     leList(?x,nil) -> true,
     leList(?x,cons(?y,?ys)) -> and(le(?x,?y),leList(?x,?ys)),
     zero(0) -> true,
     zero(s(?x)) -> false,
     prec(0) -> 0,
     prec(s(?x)) -> ?x,
     le(?x,?y) -> ifBool(zero(?x),true,le(prec(?x),prec(?y))),
     and(true,true) -> true,
     and(?x,true) -> ?x,
     and(true,?y) -> ?y,
     and(false,false) -> false,
     sort(nil) -> nil,
     sort(cons(?x,?ys)) -> insert(?x,sort(?ys)),
     insert(?x,nil) -> cons(?x,nil),
     insert(?x,cons(?y,?ys)) -> ifList(le(?x,?y),cons(?x,cons(?y,?ys)),cons(?y,insert(?x,?ys))),
     ifBool(true,?y,?z) -> ?y,
     ifBool(false,?y,?z) -> ?z,
     ifList(true,?y,?z) -> ?y,
     ifList(false,?y,?z) -> ?z,
     ordered(sort(?xs)) -> true ]
constructor detection timeout; switch to an approximation.
Constructors: {0,s,nil,cons,true,false}
Defined function symbols: {le,and,prec,sort,zero,ordered,ifBool,ifList,insert,leList}
Constructor subsystem:
   [ ]
Rule part & Conj Part:
   [ ordered(nil) -> true,
     ordered(cons(?x,?ys)) -> and(leList(?x,?ys),ordered(?ys)),
     leList(?x,nil) -> true,
     leList(?x,cons(?y,?ys)) -> and(le(?x,?y),leList(?x,?ys)),
     zero(0) -> true,
     zero(s(?x)) -> false,
     prec(0) -> 0,
     prec(s(?x)) -> ?x,
     and(?x,true) -> ?x,
     and(true,?y) -> ?y,
     and(false,false) -> false,
     sort(nil) -> nil,
     sort(cons(?x,?ys)) -> insert(?x,sort(?ys)),
     insert(?x,nil) -> cons(?x,nil),
     insert(?x,cons(?y,?ys)) -> ifList(le(?x,?y),cons(?x,cons(?y,?ys)),cons(?y,insert(?x,?ys))),
     ifBool(true,?y,?z) -> ?y,
     ifBool(false,?y,?z) -> ?z,
     ifList(true,?y,?z) -> ?y,
     ifList(false,?y,?z) -> ?z,
     le(?x,?y) -> ifBool(zero(?x),true,le(prec(?x),prec(?y))) ]
   [ and(true,true) -> true,
     ordered(sort(?xs)) -> true ]
Trying with:
R:
   [ ordered(nil) -> true,
     ordered(cons(?x,?ys)) -> and(leList(?x,?ys),ordered(?ys)),
     leList(?x,nil) -> true,
     leList(?x,cons(?y,?ys)) -> and(le(?x,?y),leList(?x,?ys)),
     zero(0) -> true,
     zero(s(?x)) -> false,
     prec(0) -> 0,
     prec(s(?x)) -> ?x,
     and(?x,true) -> ?x,
     and(true,?y) -> ?y,
     and(false,false) -> false,
     sort(nil) -> nil,
     sort(cons(?x,?ys)) -> insert(?x,sort(?ys)),
     insert(?x,nil) -> cons(?x,nil),
     insert(?x,cons(?y,?ys)) -> ifList(le(?x,?y),cons(?x,cons(?y,?ys)),cons(?y,insert(?x,?ys))),
     ifBool(true,?y,?z) -> ?y,
     ifBool(false,?y,?z) -> ?z,
     ifList(true,?y,?z) -> ?y,
     ifList(false,?y,?z) -> ?z,
     le(?x,?y) -> ifBool(zero(?x),true,le(prec(?x),prec(?y))) ]
E:
   [ and(true,true) = true,
     ordered(sort(?xs)) = true ]
*** Ground Confluence Check by Rewriting Induction ***
Sort: {Nat,Bool,List}
Signature:
   [ ordered : List -> Bool,
     leList : Nat,List -> Bool,
     zero : Nat -> Bool,
     prec : Nat -> Nat,
     le : Nat,Nat -> Bool,
     sort : List -> List,
     insert : Nat,List -> List,
     ifBool : Bool,Bool,Bool -> Bool,
     ifList : Bool,List,List -> List,
     and : Bool,Bool -> Bool,
     cons : Nat,List -> List,
     true : Bool,
     false : Bool,
     nil : List,
     s : Nat -> Nat,
     0 : Nat ]
Rule Part:
   [ ordered(nil) -> true,
     ordered(cons(?x,?ys)) -> and(leList(?x,?ys),ordered(?ys)),
     leList(?x,nil) -> true,
     leList(?x,cons(?y,?ys)) -> and(le(?x,?y),leList(?x,?ys)),
     zero(0) -> true,
     zero(s(?x)) -> false,
     prec(0) -> 0,
     prec(s(?x)) -> ?x,
     and(?x,true) -> ?x,
     and(true,?y) -> ?y,
     and(false,false) -> false,
     sort(nil) -> nil,
     sort(cons(?x,?ys)) -> insert(?x,sort(?ys)),
     insert(?x,nil) -> cons(?x,nil),
     insert(?x,cons(?y,?ys)) -> ifList(le(?x,?y),cons(?x,cons(?y,?ys)),cons(?y,insert(?x,?ys))),
     ifBool(true,?y,?z) -> ?y,
     ifBool(false,?y,?z) -> ?z,
     ifList(true,?y,?z) -> ?y,
     ifList(false,?y,?z) -> ?z,
     le(?x,?y) -> ifBool(zero(?x),true,le(prec(?x),prec(?y))) ]
Conjecture Part:
   [ and(true,true) = true,
     ordered(sort(?xs)) = true ]
Termination proof failed.
new/insert3.trs: Failure(unknown)
(1800 msec.)