YES Problem: s(p(x)) -> x p(s(x)) -> x +(x,s(y)) -> s(+(x,y)) +(x,p(y)) -> p(+(x,y)) -(x,s(y)) -> p(-(x,y)) -(x,p(y)) -> s(-(x,y)) -(p(x),y) -> p(-(x,y)) -(s(x),y) -> s(-(x,y)) Proof: Church Rosser Transformation Processor (critical pair closing system, Thm 2.11): +(x251,p(x250)) -> p(+(x251,x250)) s(p(x254)) -> x254 -(x256,p(x255)) -> s(-(x256,x255)) p(s(x259)) -> x259 -(p(x261),x260) -> p(-(x261,x260)) +(x266,s(x265)) -> s(+(x266,x265)) -(x271,s(x270)) -> p(-(x271,x270)) -(s(x276),x275) -> s(-(x276,x275)) critical peaks: joinable Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [-](x0, x1) = x0 + x1, [p](x0) = x0 + 1, [+](x0, x1) = 4x0 + 2x1 + 1 orientation: +(x251,p(x250)) = 2x250 + 4x251 + 3 >= 2x250 + 4x251 + 2 = p(+(x251,x250)) s(p(x254)) = x254 + 2 >= x254 = x254 -(x256,p(x255)) = x255 + x256 + 1 >= x255 + x256 + 1 = s(-(x256,x255)) p(s(x259)) = x259 + 2 >= x259 = x259 -(p(x261),x260) = x260 + x261 + 1 >= x260 + x261 + 1 = p(-(x261,x260)) +(x266,s(x265)) = 2x265 + 4x266 + 3 >= 2x265 + 4x266 + 2 = s(+(x266,x265)) -(x271,s(x270)) = x270 + x271 + 1 >= x270 + x271 + 1 = p(-(x271,x270)) -(s(x276),x275) = x275 + x276 + 1 >= x275 + x276 + 1 = s(-(x276,x275)) problem: -(x256,p(x255)) -> s(-(x256,x255)) -(p(x261),x260) -> p(-(x261,x260)) -(x271,s(x270)) -> p(-(x271,x270)) -(s(x276),x275) -> s(-(x276,x275)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [-](x0, x1) = 4x0 + x1, [p](x0) = x0 + 1 orientation: -(x256,p(x255)) = x255 + 4x256 + 1 >= x255 + 4x256 + 1 = s(-(x256,x255)) -(p(x261),x260) = x260 + 4x261 + 4 >= x260 + 4x261 + 1 = p(-(x261,x260)) -(x271,s(x270)) = x270 + 4x271 + 1 >= x270 + 4x271 + 1 = p(-(x271,x270)) -(s(x276),x275) = x275 + 4x276 + 4 >= x275 + 4x276 + 1 = s(-(x276,x275)) problem: -(x256,p(x255)) -> s(-(x256,x255)) -(x271,s(x270)) -> p(-(x271,x270)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [-](x0, x1) = x0 + 2x1, [p](x0) = x0 + 2 orientation: -(x256,p(x255)) = 2x255 + x256 + 4 >= 2x255 + x256 + 1 = s(-(x256,x255)) -(x271,s(x270)) = 2x270 + x271 + 2 >= 2x270 + x271 + 2 = p(-(x271,x270)) problem: -(x271,s(x270)) -> p(-(x271,x270)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 4, [-](x0, x1) = x0 + x1 + 5, [p](x0) = x0 + 3 orientation: -(x271,s(x270)) = x270 + x271 + 9 >= x270 + x271 + 8 = p(-(x271,x270)) problem: Qed