YES We show the termination of the TRS R: f(g(x)) -> g(f(f(x))) f(h(x)) -> h(g(x)) |f'|(s(x),y,y) -> |f'|(y,x,s(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) p3: |f'|#(s(x),y,y) -> |f'|#(y,x,s(x)) and R consists of: r1: f(g(x)) -> g(f(f(x))) r2: f(h(x)) -> h(g(x)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) The estimated dependency graph contains the following SCCs: {p1, p2} {p3} -- 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)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) The set of usable rules consists of r1, r2 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = x1 + 2 g_A(x1) = x1 + 2 f_A(x1) = x1 h_A(x1) = 0 precedence: f > f# = g > h partial status: pi(f#) = [1] pi(g) = [1] pi(f) = [] pi(h) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = x1 + 5 g_A(x1) = x1 + 5 f_A(x1) = 5 h_A(x1) = 15 precedence: g = f = h > f# partial status: pi(f#) = [1] pi(g) = [1] pi(f) = [] pi(h) = [] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: |f'|#(s(x),y,y) -> |f'|#(y,x,s(x)) and R consists of: r1: f(g(x)) -> g(f(f(x))) r2: f(h(x)) -> h(g(x)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: |f'|#_A(x1,x2,x3) = max{x1 + 2, x2 + 3, x3 + 1} s_A(x1) = max{5, x1 + 2} precedence: |f'|# = s partial status: pi(|f'|#) = [1, 2, 3] pi(s) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: |f'|#_A(x1,x2,x3) = max{x1 + 1, x2 + 2, x3 + 2} s_A(x1) = max{3, x1} precedence: |f'|# = s partial status: pi(|f'|#) = [] pi(s) = [1] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.