YES We show the termination of the TRS R: f(|0|()) -> s(|0|()) f(s(|0|())) -> s(|0|()) f(s(s(x))) -> f(f(s(x))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(s(x))) -> f#(f(s(x))) p2: f#(s(s(x))) -> f#(s(x)) and R consists of: r1: f(|0|()) -> s(|0|()) r2: f(s(|0|())) -> s(|0|()) r3: f(s(s(x))) -> f(f(s(x))) 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#(s(s(x))) -> f#(f(s(x))) p2: f#(s(s(x))) -> f#(s(x)) and R consists of: r1: f(|0|()) -> s(|0|()) r2: f(s(|0|())) -> s(|0|()) r3: f(s(s(x))) -> f(f(s(x))) The set of usable rules consists of r1, r2, r3 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: f#_A(x1) = 0 s_A(x1) = max{0, x1 - 3} f_A(x1) = max{1, x1 - 3} |0|_A = 2 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1) = max{0, x1 - 9} s_A(x1) = x1 + 4 f_A(x1) = max{5, x1 - 9} |0|_A = 1 f#!_A(x1) = max{1, x1 - 6} s!_A(x1) = 3 f!_A(x1) = max{4, x1 - 9} |0|!_A = 5 partial status: pi(f#) = [] pi(s) = [] pi(f) = [] pi(|0|) = [] The following rules are removed: p1, p2 Then no dependency pair remains.