Problem: +(0(),y) -> y +(x,s(y)) -> s(+(x,y)) +(x,y) -> +(y,x) Proof: AT confluence processor Complete TRS T' of input TRS: +(0(),y) -> y +(x,s(y)) -> s(+(x,y)) +(y,0()) -> y +(s(y),x) -> s(+(y,x)) +(x,y) -> +(y,x) T' = (P union S) with TRS P:+(x,y) -> +(y,x) TRS S:+(0(),y) -> y +(x,s(y)) -> s(+(x,y)) +(y,0()) -> y +(s(y),x) -> s(+(y,x)) S is linear and P is reversible. CP(S,S) = s(y) = s(+(0(),y)), 0() = 0(), s(+(0(),x209)) = s(x209), s(+(s(y),x211)) = s(+(y,s(x211))), s(y) = s(+(y,0())), s(+(x214,s(y))) = s(+(s(x214),y)), s(+(x216,0())) = s(x216) CP(S,P union P^-1) = y = +(y,0()), x = +(x,0()), s(+(x,x233)) = +(s(x233),x), s(+(y,x235)) = +(s(x235),y), x = +(0(),x), y = +(0(),y), s(+(x238,y)) = +(y,s(x238)), s(+(x240,x)) = +(x,s(x240)) CP(P union P^-1,S) = +(y,0()) = y, +(s(y),x) = s(+(x,y)), +(0(),y) = y, +(x,s(y)) = s(+(y,x)) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [+](x0, x1) = 3x0 + 4x1, [0] = 6, [s](x0) = x0 + 6 orientation: +(0(),y) = 4y + 18 >= y = y +(x,s(y)) = 3x + 4y + 24 >= 3x + 4y + 6 = s(+(x,y)) +(y,0()) = 3y + 24 >= y = y +(s(y),x) = 4x + 3y + 18 >= 4x + 3y + 6 = s(+(y,x)) problem: Qed