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: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1) = 0 g_A(x1) = 0 f_A(x1) = 0 h_A(x1) = 0 f#!_A(x1) = 0 g!_A(x1) = 2 f!_A(x1) = max{1, x1 - 2} h!_A(x1) = max{0, x1 - 3} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: f#_A(x1) = 0 g_A(x1) = x1 + 1 f_A(x1) = x1 h_A(x1) = 1 f#!_A(x1) = x1 + 2 g!_A(x1) = 1 f!_A(x1) = 0 h!_A(x1) = 2 partial status: pi(f#) = [] pi(g) = [] pi(f) = [1] pi(h) = [] The following rules are removed: p1, p2 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: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: |f'|#_A(x1,x2,x3) = 0 s_A(x1) = x1 + 7 |f'|#!_A(x1,x2,x3) = max{1, x1 - 4, x2 - 3, x3 - 8} s!_A(x1) = max{4, x1 - 3} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: |f'|#_A(x1,x2,x3) = 0 s_A(x1) = x1 + 1 |f'|#!_A(x1,x2,x3) = 1 s!_A(x1) = 0 partial status: pi(|f'|#) = [1, 2] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.