Problem: +(x,0()) -> x +(x,s(y)) -> s(+(y,x)) +(x,y) -> +(y,x) Proof: AT confluence processor Complete TRS T' of input TRS: +(x,0()) -> x +(x,s(y)) -> s(+(y,x)) +(0(),x) -> x +(s(y),x) -> s(+(x,y)) +(x,y) -> +(y,x) T' = (P union S) with TRS P:+(x,y) -> +(y,x) TRS S:+(x,0()) -> x +(x,s(y)) -> s(+(y,x)) +(0(),x) -> x +(s(y),x) -> s(+(x,y)) S is linear and P is reversible. CP(S,S) = 0() = 0(), s(y) = s(+(0(),y)), s(+(x209,0())) = s(x209), s(+(x211,s(y))) = s(+(s(x211),y)), s(y) = s(+(y,0())), s(+(0(),x214)) = s(x214), s(+(s(y),x216)) = s(+(y,s(x216))) CP(S,P union P^-1) = x = +(0(),x), y = +(0(),y), s(+(x233,x)) = +(s(x233),x), s(+(x235,y)) = +(s(x235),y), y = +(y,0()), x = +(x,0()), s(+(y,x238)) = +(y,s(x238)), s(+(x,x240)) = +(x,s(x240)) CP(P union P^-1,S) = +(0(),x) = x, +(s(y),x) = s(+(y,x)), +(x,0()) = x, +(x,s(y)) = s(+(x,y)) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [+](x0, x1) = 2x0 + 2x1 + 3, [0] = 0 orientation: +(x,0()) = 2x + 3 >= x = x +(x,s(y)) = 2x + 2y + 5 >= 2x + 2y + 4 = s(+(y,x)) +(0(),x) = 2x + 3 >= x = x +(s(y),x) = 2x + 2y + 5 >= 2x + 2y + 4 = s(+(x,y)) problem: Qed