YES(?,O(n^1)) 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: 1 enrichment: match automaton: final states: {7,4} transitions: minux0(7) -> 7*,4 minux0(4) -> 7*,4 +0(4,4) -> 7*,4 +0(7,7) -> 7* +0(4,7) -> 7*,4 +0(7,4) -> 7*,4 +1(7,5) -> 7*,4 +1(7,7) -> 7*,4 +1(6,5) -> 7*,4 +1(6,7) -> 7*,4 minus1(5) -> 4,7*,6 minus1(7) -> 4,7* minus1(4) -> 7*,4,6,5 minus1(6) -> 4,7*,5 4 -> 7* 5 -> 4* 6 -> 4* 7 -> 4* problem: Qed