YES Problem: -(0(),y) -> 0() -(x,0()) -> x -(x,s(y)) -> if(greater(x,s(y)),s(-(x,p(s(y)))),0()) p(0()) -> 0() p(s(x)) -> x Proof: DP Processor: DPs: -#(x,s(y)) -> p#(s(y)) -#(x,s(y)) -> -#(x,p(s(y))) TRS: -(0(),y) -> 0() -(x,0()) -> x -(x,s(y)) -> if(greater(x,s(y)),s(-(x,p(s(y)))),0()) p(0()) -> 0() p(s(x)) -> x Usable Rule Processor: DPs: -#(x,s(y)) -> p#(s(y)) -#(x,s(y)) -> -#(x,p(s(y))) TRS: p(s(x)) -> x Matrix Interpretation Processor: dim=4 usable rules: p(s(x)) -> x interpretation: [p#](x0) = [1 0 0 0]x0, [-#](x0, x1) = [0 0 0 1]x1, [0 0 1 0] [0 1 1 0] [p](x0) = [0 0 1 1]x0 [1 0 0 0] , [0 0 0 1] [0] [0 0 1 0] [1] [s](x0) = [1 1 1 0]x0 + [1] [0 0 0 1] [1] orientation: -#(x,s(y)) = [0 0 0 1]y + [1] >= [0 0 0 1]y = p#(s(y)) -#(x,s(y)) = [0 0 0 1]y + [1] >= [0 0 0 1]y = -#(x,p(s(y))) [1 1 1 0] [1] [1 1 2 0] [2] p(s(x)) = [1 1 1 1]x + [2] >= x = x [0 0 0 1] [0] problem: DPs: TRS: p(s(x)) -> x Qed