MAYBE

Problem:
 strict:
  g(x,y) -> x
  g(x,y) -> y
  f(0(),1(),x) -> f(s(x),x,x)
  f(x,y,s(z)) -> s(f(0(),1(),z))
 weak:
  rand(x) -> x
  rand(x) -> rand(s(x))

Proof:
 Open