MAYBE

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

Strict Trs:
  { tower(x) -> f(a(), x, s(0()))
  , f(a(), s(x), y) -> f(b(), y, s(x))
  , f(a(), 0(), y) -> y
  , f(b(), y, x) -> f(a(), half(x), exp(y))
  , half(s(s(x))) -> s(half(x))
  , half(s(0())) -> half(0())
  , half(0()) -> double(0())
  , exp(s(x)) -> double(exp(x))
  , exp(0()) -> s(0())
  , double(s(x)) -> s(s(double(x)))
  , double(0()) -> 0() }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..