Problem: +(x,0()) -> x +(s(x),y) -> s(+(y,x)) +(x,y) -> +(y,x) Proof: AT confluence processor Complete TRS T' of input TRS: +(x,0()) -> x +(s(x),y) -> s(+(y,x)) +(0(),x) -> x +(y,s(x)) -> s(+(x,y)) +(x,y) -> +(y,x) T' = (P union S) with TRS P:+(x,y) -> +(y,x) TRS S:+(x,0()) -> x +(s(x),y) -> s(+(y,x)) +(0(),x) -> x +(y,s(x)) -> s(+(x,y)) S is linear and P is reversible. CP(S,S) = s(x) = s(+(0(),x)), 0() = 0(), s(+(0(),x208)) = s(x208), s(+(s(x),x210)) = s(+(x,s(x210))), s(x) = s(+(x,0())), s(+(x215,s(x))) = s(+(s(x215),x)), s(+(x217,0())) = s(x217) CP(S,P union P^-1) = x = +(0(),x), y = +(0(),y), s(+(y,x232)) = +(y,s(x232)), s(+(x,x234)) = +(x,s(x234)), y = +(y,0()), x = +(x,0()), s(+(x239,x)) = +(s(x239),x), s(+(x241,y)) = +(s(x241),y) CP(P union P^-1,S) = +(0(),x) = x, +(y,s(x)) = s(+(y,x)), +(x,0()) = x, +(s(x),y) = s(+(x,y)) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [+](x0, x1) = 4x0 + 4x1 + 6, [0] = 0, [s](x0) = x0 + 4 orientation: +(x,0()) = 4x + 6 >= x = x +(s(x),y) = 4x + 4y + 22 >= 4x + 4y + 10 = s(+(y,x)) +(0(),x) = 4x + 6 >= x = x +(y,s(x)) = 4x + 4y + 22 >= 4x + 4y + 10 = s(+(x,y)) problem: Qed