YES Problem: E(+(x,y)) -> *(E(x),E(y)) E(0()) -> 1() +(x,0()) -> x +(0(),x) -> x *(x,1()) -> x *(1(),x) -> x +(+(x,y),z) -> +(x,+(y,z)) +(x,+(y,z)) -> +(+(x,y),z) +(x,y) -> +(y,x) *(*(x,y),z) -> *(x,*(y,z)) *(x,*(y,z)) -> *(*(x,y),z) *(x,y) -> *(y,x) Proof: Church Rosser Transformation Processor (ac): E(f5_AC(x,y)) -> f6_AC(E(x),E(y)) E(0()) -> 1() f5_AC(x,0()) -> x f5_AC(0(),x) -> x f6_AC(x,1()) -> x f6_AC(1(),x) -> x AC critical peaks: joinable AC-KBO Processor: precedence: E > 0 > 1 > f6_AC > f5_AC weight function: w0 = 2 w(0) = 7 w(1) = 2 w(f6_AC) = w(f5_AC) = w(E) = 0 problem: Qed