YES Problem: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Proof: DP Processor: DPs: f#(s(x),y) -> f#(x,s(x)) f#(x,s(y)) -> f#(y,x) f#(c(x),y) -> f#(x,s(x)) TRS: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Usable Rule Processor: DPs: f#(s(x),y) -> f#(x,s(x)) f#(x,s(y)) -> f#(y,x) f#(c(x),y) -> f#(x,s(x)) TRS: Arctic Interpretation Processor: dimension: 1 usable rules: interpretation: [f#](x0, x1) = 1x0 + x1, [c](x0) = 6x0 + 3, [s](x0) = 6x0 + 1 orientation: f#(s(x),y) = 7x + y + 2 >= 6x + 1 = f#(x,s(x)) f#(x,s(y)) = 1x + 6y + 1 >= x + 1y = f#(y,x) f#(c(x),y) = 7x + y + 4 >= 6x + 1 = f#(x,s(x)) problem: DPs: TRS: Qed