YES Problem: +(*(x,y),*(x,z)) -> *(x,+(y,z)) +(+(x,y),z) -> +(x,+(y,z)) +(*(x,y),+(*(x,z),u())) -> +(*(x,+(y,z)),u()) Proof: DP Processor: DPs: +#(*(x,y),*(x,z)) -> +#(y,z) +#(+(x,y),z) -> +#(y,z) +#(+(x,y),z) -> +#(x,+(y,z)) +#(*(x,y),+(*(x,z),u())) -> +#(y,z) +#(*(x,y),+(*(x,z),u())) -> +#(*(x,+(y,z)),u()) TRS: +(*(x,y),*(x,z)) -> *(x,+(y,z)) +(+(x,y),z) -> +(x,+(y,z)) +(*(x,y),+(*(x,z),u())) -> +(*(x,+(y,z)),u()) KBO Processor: argument filtering: pi(*) = [0,1] pi(+) = [0,1] pi(u) = [] pi(+#) = [0,1] usable rules: +(*(x,y),*(x,z)) -> *(x,+(y,z)) +(+(x,y),z) -> +(x,+(y,z)) +(*(x,y),+(*(x,z),u())) -> +(*(x,+(y,z)),u()) weight function: w0 = 1 w(+#) = w(u) = w(+) = w(*) = 1 precedence: +# ~ u ~ + ~ * problem: DPs: TRS: +(*(x,y),*(x,z)) -> *(x,+(y,z)) +(+(x,y),z) -> +(x,+(y,z)) +(*(x,y),+(*(x,z),u())) -> +(*(x,+(y,z)),u()) Qed