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