YES We show the termination of the TRS R: f(c(X,s(Y))) -> f(c(s(X),Y)) g(c(s(X),Y)) -> f(c(X,s(Y))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(X,s(Y))) -> f#(c(s(X),Y)) p2: g#(c(s(X),Y)) -> f#(c(X,s(Y))) and R consists of: r1: f(c(X,s(Y))) -> f(c(s(X),Y)) r2: g(c(s(X),Y)) -> f(c(X,s(Y))) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(X,s(Y))) -> f#(c(s(X),Y)) and R consists of: r1: f(c(X,s(Y))) -> f(c(s(X),Y)) r2: g(c(s(X),Y)) -> f(c(X,s(Y))) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: f#_A(x1) = x1 + (3,1) c_A(x1,x2) = x2 + (1,1) s_A(x1) = x1 + (2,3) precedence: f# = c = s partial status: pi(f#) = [] pi(c) = [] pi(s) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: f#_A(x1) = x1 c_A(x1,x2) = x2 s_A(x1) = x1 + (1,1) precedence: f# > c = s partial status: pi(f#) = [1] pi(c) = [] pi(s) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.