MAYBE

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

Strict Trs:
  { or(x, true()) -> true()
  , or(true(), y) -> true()
  , or(false(), false()) -> false()
  , mem(x, nil()) -> false()
  , mem(x, set(y)) -> =(x, y)
  , mem(x, union(y, z)) -> or(mem(x, y), mem(x, z)) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..