YES We show the termination of the TRS R: f(empty(),l) -> l f(cons(x,k),l) -> g(k,l,cons(x,k)) g(a,b,c) -> f(a,cons(b,c)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(cons(x,k),l) -> g#(k,l,cons(x,k)) p2: g#(a,b,c) -> f#(a,cons(b,c)) and R consists of: r1: f(empty(),l) -> l r2: f(cons(x,k),l) -> g(k,l,cons(x,k)) r3: g(a,b,c) -> f(a,cons(b,c)) 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#(cons(x,k),l) -> g#(k,l,cons(x,k)) p2: g#(a,b,c) -> f#(a,cons(b,c)) and R consists of: r1: f(empty(),l) -> l r2: f(cons(x,k),l) -> g(k,l,cons(x,k)) r3: g(a,b,c) -> f(a,cons(b,c)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. max/plus interpretations on natural numbers: f#_A(x1,x2) = x1 + 6 cons_A(x1,x2) = max{x1, x2 + 4} g#_A(x1,x2,x3) = max{x1 + 7, x3 + 3} 2. max/plus interpretations on natural numbers: f#_A(x1,x2) = 1 cons_A(x1,x2) = 0 g#_A(x1,x2,x3) = 0 The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.