YES

Problem:
 minus(minus(x)) -> x
 minux(+(x,y)) -> +(minus(y),minus(x))
 +(minus(x),+(x,y)) -> y
 +(+(x,y),minus(y)) -> x

Proof:
 Bounds Processor:
  bound: 0
  enrichment: roof
  automaton:
   final states: {8,2,1}
   transitions:
    minus0(1) -> 7*,4,3
    minus0(8) -> 7*
    f30() -> 8*,4,3,2,1
    +0(8,3) -> 2*
    +0(8,7) -> 2*
    +0(4,8) -> 2*
    +0(7,3) -> 2*
    +0(7,7) -> 2*
    +0(8,8) -> 2*
    +0(4,3) -> 2*
    +0(4,7) -> 2*
    +0(7,8) -> 2*
    1 -> 2,3,4
  problem:
   
  Qed