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. matrix interpretations: carrier: N^1 order: standard order interpretations: a#_A(x1) = x1 b_A(x1) = x1 a_A(x1) = x1 + 1 2. lexicographic path order with precedence: precedence: b > a > a# argument filter: 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.