YES We show the termination of the TRS R: f(|0|()) -> cons(|0|(),n__f(n__s(n__0()))) f(s(|0|())) -> f(p(s(|0|()))) p(s(X)) -> X f(X) -> n__f(X) s(X) -> n__s(X) |0|() -> n__0() activate(n__f(X)) -> f(activate(X)) activate(n__s(X)) -> s(activate(X)) activate(n__0()) -> |0|() activate(X) -> X -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(|0|())) -> f#(p(s(|0|()))) p2: f#(s(|0|())) -> p#(s(|0|())) p3: activate#(n__f(X)) -> f#(activate(X)) p4: activate#(n__f(X)) -> activate#(X) p5: activate#(n__s(X)) -> s#(activate(X)) p6: activate#(n__s(X)) -> activate#(X) p7: activate#(n__0()) -> |0|#() and R consists of: r1: f(|0|()) -> cons(|0|(),n__f(n__s(n__0()))) r2: f(s(|0|())) -> f(p(s(|0|()))) r3: p(s(X)) -> X r4: f(X) -> n__f(X) r5: s(X) -> n__s(X) r6: |0|() -> n__0() r7: activate(n__f(X)) -> f(activate(X)) r8: activate(n__s(X)) -> s(activate(X)) r9: activate(n__0()) -> |0|() r10: activate(X) -> X The estimated dependency graph contains the following SCCs: {p4, p6} {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: activate#(n__s(X)) -> activate#(X) p2: activate#(n__f(X)) -> activate#(X) and R consists of: r1: f(|0|()) -> cons(|0|(),n__f(n__s(n__0()))) r2: f(s(|0|())) -> f(p(s(|0|()))) r3: p(s(X)) -> X r4: f(X) -> n__f(X) r5: s(X) -> n__s(X) r6: |0|() -> n__0() r7: activate(n__f(X)) -> f(activate(X)) r8: activate(n__s(X)) -> s(activate(X)) r9: activate(n__0()) -> |0|() r10: activate(X) -> X The set of usable rules consists of (no rules) Take the monotone reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: activate#_A(x1) = x1 + 1 n__s_A(x1) = x1 n__f_A(x1) = x1 precedence: activate# = n__s = n__f partial status: pi(activate#) = [] pi(n__s) = [] pi(n__f) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: activate#_A(x1) = x1 + 1 n__s_A(x1) = x1 n__f_A(x1) = x1 precedence: activate# = n__s = n__f partial status: pi(activate#) = [1] pi(n__s) = [1] pi(n__f) = [1] 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(|0|())) -> f#(p(s(|0|()))) and R consists of: r1: f(|0|()) -> cons(|0|(),n__f(n__s(n__0()))) r2: f(s(|0|())) -> f(p(s(|0|()))) r3: p(s(X)) -> X r4: f(X) -> n__f(X) r5: s(X) -> n__s(X) r6: |0|() -> n__0() r7: activate(n__f(X)) -> f(activate(X)) r8: activate(n__s(X)) -> s(activate(X)) r9: activate(n__0()) -> |0|() r10: activate(X) -> X The set of usable rules consists of r3, r5, r6 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = max{8, x1 + 7} s_A(x1) = x1 + 3 |0|_A = 4 p_A(x1) = max{3, x1} n__s_A(x1) = max{3, x1 + 2} n__0_A = 0 precedence: s = |0| > f# = p = n__s = n__0 partial status: pi(f#) = [1] pi(s) = [1] pi(|0|) = [] pi(p) = [] pi(n__s) = [1] pi(n__0) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = max{11, x1 + 3} s_A(x1) = max{8, x1 + 5} |0|_A = 1 p_A(x1) = 0 n__s_A(x1) = max{9, x1 + 6} n__0_A = 2 precedence: f# = s = |0| = p = n__s = n__0 partial status: pi(f#) = [1] pi(s) = [1] pi(|0|) = [] pi(p) = [] pi(n__s) = [] pi(n__0) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.