YES(?,PRIMREC)

We are left with following problem, upon which TcT provides the
certificate YES(?,PRIMREC).

Strict Trs:
  { f(0(x1)) -> s(0(x1))
  , f(s(x1)) -> d(f(x1))
  , d(0(x1)) -> 0(x1)
  , d(s(x1)) -> s(s(d(x1))) }
Obligation:
  innermost runtime complexity
Answer:
  YES(?,PRIMREC)

The input was oriented with the instance of'multiset path order' as
induced by the precedence

 f > s, f > d, 0 > s, 0 > d, d > s, f ~ 0 .

Hurray, we answered YES(?,PRIMREC)