YES We show the termination of the TRS R: f(x,c(y)) -> f(x,s(f(y,y))) f(s(x),y) -> f(x,s(c(y))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(x,c(y)) -> f#(x,s(f(y,y))) p2: f#(x,c(y)) -> f#(y,y) p3: f#(s(x),y) -> f#(x,s(c(y))) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(y))) The estimated dependency graph contains the following SCCs: {p2} {p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(x,c(y)) -> f#(y,y) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(y))) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1 + 5, x2} c_A(x1) = x1 + 5 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1, x2 - 3} c_A(x1) = x1 + 3 f#!_A(x1,x2) = max{0, x1 - 5} c!_A(x1) = max{2, x1 - 4} partial status: pi(f#) = [1, 2] pi(c) = [1] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(c(y))) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(y))) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: f#_A(x1,x2) = x2 + 5 s_A(x1) = max{0, x1 - 12} c_A(x1) = x1 + 8 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{0, x1 - 21, x2 - 16} s_A(x1) = x1 + 6 c_A(x1) = max{9, x1 - 34} f#!_A(x1,x2) = max{2, x1 - 3} s!_A(x1) = max{5, x1 - 8} c!_A(x1) = max{4, x1 - 30} partial status: pi(f#) = [] pi(s) = [] pi(c) = [] The following rules are removed: p1 Then no dependency pair remains.