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: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1, x2 - 2} c_A(x1) = max{10, x1 + 2} f#!_A(x1,x2) = max{1, x1 - 33, x2 - 34} c!_A(x1) = max{2, x1 - 33} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: f#_A(x1,x2) = x2 c_A(x1) = x1 + 1 f#!_A(x1,x2) = x2 + 2 c!_A(x1) = 1 partial status: pi(f#) = [] pi(c) = [] 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: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{0, x1 - 29, x2 - 28} s_A(x1) = max{17, x1 + 5} c_A(x1) = max{22, x1 - 25} f#!_A(x1,x2) = max{4, x1 - 18, x2 - 29} s!_A(x1) = max{2, x1 - 19} c!_A(x1) = max{1, x1 - 31} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: f#_A(x1,x2) = x1 + x2 s_A(x1) = x1 + 2 c_A(x1) = x1 f#!_A(x1,x2) = x1 + x2 + 1 s!_A(x1) = 2 c!_A(x1) = 0 partial status: pi(f#) = [1] pi(s) = [1] pi(c) = [] The following rules are removed: p1 Then no dependency pair remains.