MAYBE
MAYBE
TRS:
 {
                sqr(s(X)) -> s(add(sqr(X), dbl(X))),
                 sqr(0()) -> 0(),
                 terms(N) -> cons(recip(sqr(N)), terms(s(N))),
             add(s(X), Y) -> s(add(X, Y)),
              add(0(), X) -> X,
                dbl(s(X)) -> s(s(dbl(X))),
                 dbl(0()) -> 0(),
  first(s(X), cons(Y, Z)) -> cons(Y, first(X, Z)),
            first(0(), X) -> nil(),
            half(s(s(X))) -> s(half(X)),
             half(s(0())) -> 0(),
                half(0()) -> 0(),
             half(dbl(X)) -> X
 }
 DUP: We consider a duplicating system.
  Trs:
   {
                  sqr(s(X)) -> s(add(sqr(X), dbl(X))),
                   sqr(0()) -> 0(),
                   terms(N) -> cons(recip(sqr(N)), terms(s(N))),
               add(s(X), Y) -> s(add(X, Y)),
                add(0(), X) -> X,
                  dbl(s(X)) -> s(s(dbl(X))),
                   dbl(0()) -> 0(),
    first(s(X), cons(Y, Z)) -> cons(Y, first(X, Z)),
              first(0(), X) -> nil(),
              half(s(s(X))) -> s(half(X)),
               half(s(0())) -> 0(),
                  half(0()) -> 0(),
               half(dbl(X)) -> X
   }
  Fail