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. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1,x2) = max{x1 + 5, x2} cons_A(x1,x2) = max{3, x2 + 1} g#_A(x1,x2,x3) = max{x1 + 6, x2 - 1, x3 + 2} precedence: f# = cons = g# partial status: pi(f#) = [1, 2] pi(cons) = [2] pi(g#) = [1, 3] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1,x2) = x1 + 3 cons_A(x1,x2) = max{6, x2 + 2} g#_A(x1,x2,x3) = max{x1 + 3, x3 + 1} precedence: f# = cons = g# partial status: pi(f#) = [] pi(cons) = [] pi(g#) = [3] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.