YES We show the termination of the TRS R: f(g(X)) -> g(f(f(X))) f(h(X)) -> h(g(X)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(g(X)) -> f#(f(X)) p2: f#(g(X)) -> f#(X) and R consists of: r1: f(g(X)) -> g(f(f(X))) r2: f(h(X)) -> h(g(X)) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(g(X)) -> f#(f(X)) p2: f#(g(X)) -> f#(X) and R consists of: r1: f(g(X)) -> g(f(f(X))) r2: f(h(X)) -> h(g(X)) The set of usable rules consists of r1, r2 Take the reduction pair: matrix interpretations: carrier: N^3 order: lexicographic order interpretations: f#_A(x1) = x1 g_A(x1) = x1 + (0,1,1) f_A(x1) = x1 + (0,0,2) h_A(x1) = (1,1,1) The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.