YES Problem: f(f(x,y),z) -> f(x,f(y,z)) f(1(),x) -> x Proof: Church Rosser Transformation Processor (kb): f(f(x,y),z) -> f(x,f(y,z)) f(1(),x) -> x critical peaks: joinable Matrix Interpretation Processor: dim=1 interpretation: [1] = 1, [f](x0, x1) = 3x0 + x1 + 4 orientation: f(f(x,y),z) = 9x + 3y + z + 16 >= 3x + 3y + z + 8 = f(x,f(y,z)) f(1(),x) = x + 7 >= x = x problem: Qed