MAYBE

We are left with following problem, upon which TcT provides the
certificate MAYBE.

Strict Trs:
  { -(x, 0()) -> x
  , -(s(x), s(y)) -> -(x, y)
  , <=(0(), y) -> true()
  , <=(s(x), 0()) -> false()
  , <=(s(x), s(y)) -> <=(x, y)
  , if(true(), x, y) -> x
  , if(false(), x, y) -> y
  , perfectp(0()) -> false()
  , perfectp(s(x)) -> f(x, s(0()), s(x), s(x))
  , f(0(), y, 0(), u) -> true()
  , f(0(), y, s(z), u) -> false()
  , f(s(x), 0(), z, u) -> f(x, u, -(z, s(x)), u)
  , f(s(x), s(y), z, u) ->
    if(<=(x, y), f(s(x), -(y, x), z, u), f(x, u, z, u)) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..