Problem: +(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(+(x,y),z) -> +(x,+(y,z)) +(x,y) -> +(y,x) Proof: AT confluence processor Complete TRS T' of input TRS: +(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(y,0()) -> y +(y,s(x)) -> s(+(y,x)) +(+(x,y),z) -> +(x,+(y,z)) +(x,y) -> +(y,x) T' = (P union S) with TRS P:+(+(x,y),z) -> +(x,+(y,z)) +(x,y) -> +(y,x) TRS S:+(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(y,0()) -> y +(y,s(x)) -> s(+(y,x)) S is linear and P is reversible. CP(S,S) = 0() = 0(), s(x) = s(+(0(),x)), s(+(x341,0())) = s(x341), s(+(x343,s(x))) = s(+(s(x343),x)), s(x) = s(+(x,0())), s(+(0(),x348)) = s(x348), s(+(s(x),x350)) = s(+(x,s(x350))) CP(S,P union P^-1) = +(y,z) = +(0(),+(y,z)), y = +(y,0()), +(y,z) = +(+(0(),y),z), +(x,z) = +(+(x,0()),z), x = +(x,0()), +(s(+(x392,y)),z) = +(s(x392),+(y,z)), s(+(x394,y)) = +(y,s(x394)), s(+(x396,+(y,z))) = +(+(s(x396),y),z), +(x,s(+(x398,z))) = +(+(x,s(x398)),z), s(+(x400,x)) = +(x,s(x400)), +(x,y) = +(x,+(y,0())), +(x,z) = +(x,+(0(),z)), x = +(0(),x), +(x,y) = +(+(x,y),0()), y = +(0(),y), s(+(+(x,y),x408)) = +(x,+(y,s(x408))), +(s(+(x,x410)),z) = +(x,+(s(x410),z)), s(+(x,x412)) = +(s(x412),x), +(x,s(+(y,x414))) = +(+(x,y),s(x414)), s(+(y,x416)) = +(s(x416),y) CP(P union P^-1,S) = +(x497,+(x498,0())) = +(x497,x498), +(x500,+(x501,s(x))) = s(+(+(x500,x501),x)), +(y,0()) = y, +(y,s(x)) = s(+(x,y)), +(0(),y) = y, +(s(x),y) = s(+(y,x)), +(+(0(),x512),x513) = +(x512,x513), +(+(s(x),x515),x516) = s(+(x,+(x515,x516))) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0, [+](x0, x1) = 2x0 + 2x1 + 1, [0] = 1 orientation: +(0(),y) = 2y + 3 >= y = y +(s(x),y) = 2x + 2y + 1 >= 2x + 2y + 1 = s(+(x,y)) +(y,0()) = 2y + 3 >= y = y +(y,s(x)) = 2x + 2y + 1 >= 2x + 2y + 1 = s(+(y,x)) problem: +(s(x),y) -> s(+(x,y)) +(y,s(x)) -> s(+(y,x)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [+](x0, x1) = x0 + 2x1 + 5 orientation: +(s(x),y) = x + 2y + 6 >= x + 2y + 6 = s(+(x,y)) +(y,s(x)) = 2x + y + 7 >= 2x + y + 6 = s(+(y,x)) problem: +(s(x),y) -> s(+(x,y)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [+](x0, x1) = 2x0 + 4x1 + 5 orientation: +(s(x),y) = 2x + 4y + 7 >= 2x + 4y + 6 = s(+(x,y)) problem: Qed