MAYBE Problem: f(x,a(b(y))) -> f(a(a(x)),y) f(x,b(a(y))) -> f(b(b(x)),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) Proof: Complexity Transformation Processor: strict: f(x,a(b(y))) -> f(a(a(x)),y) f(x,b(a(y))) -> f(b(b(x)),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) weak: Matrix Interpretation Processor: dimension: 1 max_matrix: 1 interpretation: [f](x0, x1) = x0 + x1 + 1, [a](x0) = x0 + 1, [b](x0) = x0 orientation: f(x,a(b(y))) = x + y + 2 >= x + y + 3 = f(a(a(x)),y) f(x,b(a(y))) = x + y + 2 >= x + y + 1 = f(b(b(x)),y) f(a(x),y) = x + y + 2 >= x + y + 2 = f(x,a(y)) f(b(x),y) = x + y + 1 >= x + y + 1 = f(x,b(y)) problem: strict: f(x,a(b(y))) -> f(a(a(x)),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) weak: f(x,b(a(y))) -> f(b(b(x)),y) Open