YES We show the termination of the TRS R: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) p3: f#(c(x),y) -> f#(x,s(x)) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) The estimated dependency graph contains the following SCCs: {p1, p2, p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(x)) p2: f#(c(x),y) -> f#(x,s(x)) p3: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) 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 - 18, x2 - 26} s_A(x1) = max{17, x1 + 8} c_A(x1) = x1 f#!_A(x1,x2) = max{3, x1 - 13, x2 - 21} s!_A(x1) = max{3, x1 - 3} c!_A(x1) = max{1, x1 - 12} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{0, x1 - 3, x2 - 3} s_A(x1) = max{2, x1} c_A(x1) = max{1, x1} f#!_A(x1,x2) = max{4, x1 - 5, x2 - 5} s!_A(x1) = max{3, x1 - 2} c!_A(x1) = max{1, x1 - 6} partial status: pi(f#) = [] pi(s) = [1] pi(c) = [1] The following rules are removed: p1 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,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#(c(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) 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) = 0 c_A(x1) = 9 s_A(x1) = max{15, x1 + 8} f#!_A(x1,x2) = max{3, x1 - 6, x2 - 11} c!_A(x1) = x1 + 6 s!_A(x1) = max{2, x1 - 1} 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: f#_A(x1,x2) = max{0, x1 - 7, x2 - 8} c_A(x1) = max{5, x1 + 2} s_A(x1) = max{7, x1 + 3} f#!_A(x1,x2) = max{1, x1 - 18, x2 - 17} c!_A(x1) = max{2, x1 - 9} s!_A(x1) = max{3, x1 - 5} partial status: pi(f#) = [1, 2] pi(c) = [1] pi(s) = [1] The following rules are removed: p1, p2 Then no dependency pair remains.