YES Problem: s(p(x)) -> x p(s(x)) -> x +(x,0()) -> x +(x,s(y)) -> s(+(x,y)) +(x,p(y)) -> p(+(x,y)) -(0(),0()) -> 0() -(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): +(x342,p(x341)) -> p(+(x342,x341)) s(p(x345)) -> x345 -(x347,p(x346)) -> s(-(x347,x346)) p(s(x350)) -> x350 -(p(x352),x351) -> p(-(x352,x351)) +(x357,s(x356)) -> s(+(x357,x356)) -(x362,s(x361)) -> p(-(x362,x361)) -(s(x367),x366) -> s(-(x367,x366)) critical peaks: joinable Matrix Interpretation Processor: dim=1 interpretation: [-](x0, x1) = x0 + x1, [s](x0) = x0 + 1, [+](x0, x1) = 4x0 + 2x1 + 1, [p](x0) = x0 + 1 orientation: +(x342,p(x341)) = 2x341 + 4x342 + 3 >= 2x341 + 4x342 + 2 = p(+(x342,x341)) s(p(x345)) = x345 + 2 >= x345 = x345 -(x347,p(x346)) = x346 + x347 + 1 >= x346 + x347 + 1 = s(-(x347,x346)) p(s(x350)) = x350 + 2 >= x350 = x350 -(p(x352),x351) = x351 + x352 + 1 >= x351 + x352 + 1 = p(-(x352,x351)) +(x357,s(x356)) = 2x356 + 4x357 + 3 >= 2x356 + 4x357 + 2 = s(+(x357,x356)) -(x362,s(x361)) = x361 + x362 + 1 >= x361 + x362 + 1 = p(-(x362,x361)) -(s(x367),x366) = x366 + x367 + 1 >= x366 + x367 + 1 = s(-(x367,x366)) problem: -(x347,p(x346)) -> s(-(x347,x346)) -(p(x352),x351) -> p(-(x352,x351)) -(x362,s(x361)) -> p(-(x362,x361)) -(s(x367),x366) -> s(-(x367,x366)) Matrix Interpretation Processor: dim=1 interpretation: [-](x0, x1) = 4x0 + x1, [s](x0) = x0 + 1, [p](x0) = x0 + 1 orientation: -(x347,p(x346)) = x346 + 4x347 + 1 >= x346 + 4x347 + 1 = s(-(x347,x346)) -(p(x352),x351) = x351 + 4x352 + 4 >= x351 + 4x352 + 1 = p(-(x352,x351)) -(x362,s(x361)) = x361 + 4x362 + 1 >= x361 + 4x362 + 1 = p(-(x362,x361)) -(s(x367),x366) = x366 + 4x367 + 4 >= x366 + 4x367 + 1 = s(-(x367,x366)) problem: -(x347,p(x346)) -> s(-(x347,x346)) -(x362,s(x361)) -> p(-(x362,x361)) Matrix Interpretation Processor: dim=1 interpretation: [-](x0, x1) = x0 + 2x1, [s](x0) = x0 + 1, [p](x0) = x0 + 2 orientation: -(x347,p(x346)) = 2x346 + x347 + 4 >= 2x346 + x347 + 1 = s(-(x347,x346)) -(x362,s(x361)) = 2x361 + x362 + 2 >= 2x361 + x362 + 2 = p(-(x362,x361)) problem: -(x362,s(x361)) -> p(-(x362,x361)) Matrix Interpretation Processor: dim=1 interpretation: [-](x0, x1) = x0 + x1 + 5, [s](x0) = x0 + 4, [p](x0) = x0 + 3 orientation: -(x362,s(x361)) = x361 + x362 + 9 >= x361 + x362 + 8 = p(-(x362,x361)) problem: Qed