NO Problem: f(X,g(X)) -> f(1(),g(X)) g(1()) -> g(0()) Proof: Matrix Interpretation Processor: dim=3 interpretation: [1 0 1] [1 0 0] [f](x0, x1) = [0 0 0]x0 + [0 0 0]x1 [1 0 0] [1 0 1] , [0] [0] = [0] [0], [1 1 1] [g](x0) = [0 0 0]x0 [0 0 1] , [0] [1] = [1] [0] orientation: [2 1 2] [1 1 1] f(X,g(X)) = [0 0 0]X >= [0 0 0]X = f(1(),g(X)) [2 1 2] [1 1 2] [1] [0] g(1()) = [0] >= [0] = g(0()) [0] [0] problem: f(X,g(X)) -> f(1(),g(X)) Unfolding Processor: loop length: 1 terms: f(1(),g(1())) context: [] substitution: Qed