Problem: +(x,0()) -> x +(s(x),y) -> s(+(x,y)) +(x,y) -> +(y,x) Proof: AT confluence processor Complete TRS T' of input TRS: +(x,0()) -> x +(s(x),y) -> s(+(x,y)) +(0(),x) -> x +(y,s(x)) -> s(+(y,x)) +(x,y) -> +(y,x) T' = (P union S) with TRS P:+(x,y) -> +(y,x) TRS S:+(x,0()) -> x +(s(x),y) -> s(+(x,y)) +(0(),x) -> x +(y,s(x)) -> s(+(y,x)) S is linear and P is reversible. CP(S,S) = s(x) = s(+(x,0())), 0() = 0(), s(+(x208,0())) = s(x208), s(+(x210,s(x))) = s(+(s(x210),x)), s(x) = s(+(0(),x)), s(+(s(x),x215)) = s(+(x,s(x215))), s(+(0(),x217)) = s(x217) CP(S,P union P^-1) = x = +(0(),x), y = +(0(),y), s(+(x232,y)) = +(y,s(x232)), s(+(x234,x)) = +(x,s(x234)), y = +(y,0()), x = +(x,0()), s(+(x,x239)) = +(s(x239),x), s(+(y,x241)) = +(s(x241),y) CP(P union P^-1,S) = +(0(),x) = x, +(y,s(x)) = s(+(x,y)), +(x,0()) = x, +(s(x),y) = s(+(y,x)) We have to check termination of S: Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 6, [+](x0, x1) = 4x0 + x1 + 1, [0] = 4 orientation: +(x,0()) = 4x + 5 >= x = x +(s(x),y) = 4x + y + 25 >= 4x + y + 7 = s(+(x,y)) +(0(),x) = x + 17 >= x = x +(y,s(x)) = x + 4y + 7 >= x + 4y + 7 = s(+(y,x)) problem: +(y,s(x)) -> s(+(y,x)) Matrix Interpretation Processor: dim=1 interpretation: [s](x0) = x0 + 1, [+](x0, x1) = x0 + 2x1 + 5 orientation: +(y,s(x)) = 2x + y + 7 >= 2x + y + 6 = s(+(y,x)) problem: Qed