YES(?,PRIMREC)

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

Strict Trs:
  { first(0(), X) -> nil()
  , first(s(X), cons(Y)) -> cons(Y)
  , from(X) -> cons(X) }
Obligation:
  innermost runtime complexity
Answer:
  YES(?,PRIMREC)

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

 first > nil, first > cons, 0 > nil, 0 > cons, nil > cons, s > nil,
 s > cons, from > nil, from > cons, first ~ 0, first ~ s,
 first ~ from, 0 ~ s, 0 ~ from, s ~ from .

Hurray, we answered YES(?,PRIMREC)