Problem:
 minus(0()) -> 0()
 +(x,0()) -> x
 +(0(),y) -> y
 +(minus(1()),1()) -> 0()
 minus(minus(x)) -> x
 +(x,minus(y)) -> minus(+(minus(x),y))
 +(x,+(y,z)) -> +(+(x,y),z)
 +(minus(+(x,1())),1()) -> minus(x)

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {4,3}
   transitions:
    01() -> 3*
    minus0(2) -> 3*
    minus0(1) -> 3*
    00() -> 1*
    +0(1,2) -> 4*
    +0(2,1) -> 4*
    +0(1,1) -> 4*
    +0(2,2) -> 4*
    10() -> 2*
    1 -> 4*
    2 -> 4*
  problem:
   
  Qed