MAYBE Problem: f(x,a(b(y))) -> f(a(b(x)),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) Proof: DP Processor: DPs: f#(x,a(b(y))) -> f#(a(b(x)),y) f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) TRS: f(x,a(b(y))) -> f(a(b(x)),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) Usable Rule Processor: DPs: f#(x,a(b(y))) -> f#(a(b(x)),y) f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) TRS: Open