YES We show the termination of the TRS R: a(b(a(x))) -> b(a(b(x))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: a#(b(a(x))) -> a#(b(x)) and R consists of: r1: a(b(a(x))) -> b(a(b(x))) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: a#(b(a(x))) -> a#(b(x)) and R consists of: r1: a(b(a(x))) -> b(a(b(x))) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: a#_A(x1) = max{11, x1 + 5} b_A(x1) = max{3, x1 + 2} a_A(x1) = x1 + 4 precedence: a# = b = a partial status: pi(a#) = [1] pi(b) = [1] pi(a) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: a#_A(x1) = max{8, x1 - 2} b_A(x1) = x1 + 6 a_A(x1) = x1 + 1 precedence: a# = b = a partial status: pi(a#) = [] pi(b) = [1] pi(a) = [1] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.