Problem:
 *(x,*(y,z)) -> *(*(x,y),z)
 *(x,x) -> x

Proof:
 Bounds Processor:
  bound: 0
  enrichment: match
  automaton:
   final states: {3,2}
   transitions:
    *0(3,1) -> 2*
    *0(3,3) -> 2*
    *0(1,1) -> 2*
    *0(1,3) -> 2*
    f20() -> 3*,2,1
    1 -> 2*
    3 -> 2*
  problem:
   
  Qed