Problem: +(x,0()) -> x +(x,s(y)) -> s(+(x,y)) +(0(),y) -> y +(s(x),y) -> s(+(x,y)) *(1(),0()) -> 0() *(1(),s(y)) -> s(*(1(),y)) +(x,y) -> +(y,x) +(+(x,y),z) -> +(x,+(y,z)) Proof: AT confluence processor Complete TRS T' of input TRS: +(x,0()) -> x +(x,s(y)) -> s(+(x,y)) +(0(),y) -> y +(s(x),y) -> s(+(x,y)) *(1(),0()) -> 0() *(1(),s(y)) -> s(*(1(),y)) +(x,y) -> +(y,x) +(+(x,y),z) -> +(x,+(y,z)) T' = (P union S) with TRS P:+(x,y) -> +(y,x) +(+(x,y),z) -> +(x,+(y,z)) TRS S:+(x,0()) -> x +(x,s(y)) -> s(+(x,y)) +(0(),y) -> y +(s(x),y) -> s(+(x,y)) *(1(),0()) -> 0() *(1(),s(y)) -> s(*(1(),y)) S is linear and P is reversible. CP(S,S) = 0() = 0(), s(x) = s(+(x,0())), s(+(0(),x454)) = s(x454), s(+(s(x),x456)) = s(+(x,s(x456))), s(y) = s(+(0(),y)), s(+(x459,0())) = s(x459), s(+(x461,s(y))) = s(+(s(x461),y)) CP(S,P union P^-1) = x = +(0(),x), +(x,y) = +(x,+(y,0())), +(x,z) = +(x,+(0(),z)), y = +(0(),y), +(x,y) = +(+(x,y),0()), s(+(x,x511)) = +(s(x511),x), s(+(+(x,y),x513)) = +(x,+(y,s(x513))), +(s(+(x,x515)),z) = +(x,+(s(x515),z)), s(+(y,x517)) = +(s(x517),y), +(x,s(+(y,x519))) = +(+(x,y),s(x519)), y = +(y,0()), +(y,z) = +(0(),+(y,z)), x = +(x,0()), +(y,z) = +(+(0(),y),z), +(x,z) = +(+(x,0()),z), s(+(x525,y)) = +(y,s(x525)), +(s(+(x527,y)),z) = +(s(x527),+(y,z)), s(+(x529,x)) = +(x,s(x529)), s(+(x531,+(y,z))) = +(+(s(x531),y),z), +(x,s(+(x533,z))) = +(+(x,s(x533)),z) CP(P union P^-1,S) = +(0(),x) = x, +(s(y),x) = s(+(x,y)), +(y,0()) = y, +(y,s(x)) = s(+(x,y)), +(x683,+(x684,0())) = +(x683,x684), +(x686,+(x687,s(y))) = s(+(+(x686,x687),y)), +(+(0(),x698),x699) = +(x698,x699), +(+(s(x),x701),x702) = s(+(x,+(x701,x702))) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [*](x0, x1) = x0 + x1, [+](x0, x1) = x0 + x1, [1] = 0, [0] = 1, [s](x0) = x0 + 2 orientation: +(x,0()) = x + 1 >= x = x +(x,s(y)) = x + y + 2 >= x + y + 2 = s(+(x,y)) +(0(),y) = y + 1 >= y = y +(s(x),y) = x + y + 2 >= x + y + 2 = s(+(x,y)) *(1(),0()) = 1 >= 1 = 0() *(1(),s(y)) = y + 2 >= y + 2 = s(*(1(),y)) problem: +(x,s(y)) -> s(+(x,y)) +(s(x),y) -> s(+(x,y)) *(1(),0()) -> 0() *(1(),s(y)) -> s(*(1(),y)) Matrix Interpretation Processor: dim=1 interpretation: [*](x0, x1) = 4x0 + x1 + 1, [+](x0, x1) = x0 + 4x1 + 1, [1] = 4, [0] = 4, [s](x0) = x0 + 3 orientation: +(x,s(y)) = x + 4y + 13 >= x + 4y + 4 = s(+(x,y)) +(s(x),y) = x + 4y + 4 >= x + 4y + 4 = s(+(x,y)) *(1(),0()) = 21 >= 4 = 0() *(1(),s(y)) = y + 20 >= y + 20 = s(*(1(),y)) problem: +(s(x),y) -> s(+(x,y)) *(1(),s(y)) -> s(*(1(),y)) Matrix Interpretation Processor: dim=1 interpretation: [*](x0, x1) = x0 + 5x1 + 4, [+](x0, x1) = x0 + 4x1, [1] = 4, [s](x0) = x0 + 1 orientation: +(s(x),y) = x + 4y + 1 >= x + 4y + 1 = s(+(x,y)) *(1(),s(y)) = 5y + 13 >= 5y + 9 = s(*(1(),y)) problem: +(s(x),y) -> s(+(x,y)) Matrix Interpretation Processor: dim=1 interpretation: [+](x0, x1) = 2x0 + 4x1 + 7, [s](x0) = x0 + 1 orientation: +(s(x),y) = 2x + 4y + 9 >= 2x + 4y + 8 = s(+(x,y)) problem: Qed