MAYBE

Problem:
 strict:
  tests(0()) -> true()
  tests(s(x)) -> and(test(rands(rand(0()),nil())),x)
  test(done(y)) -> eq(f(y),g(y))
  eq(x,x) -> true()
  rands(0(),y) -> done(y)
  rands(s(x),y) -> rands(x,::(rand(0()),y))
 weak:
  rand(x) -> x
  rand(x) -> rand(s(x))

Proof:
 Open