YES We show the termination of the TRS R: p(a(x0),p(b(x1),p(a(x2),x3))) -> p(x2,p(a(a(x0)),p(b(x1),x3))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: p#(a(x0),p(b(x1),p(a(x2),x3))) -> p#(x2,p(a(a(x0)),p(b(x1),x3))) p2: p#(a(x0),p(b(x1),p(a(x2),x3))) -> p#(a(a(x0)),p(b(x1),x3)) p3: p#(a(x0),p(b(x1),p(a(x2),x3))) -> p#(b(x1),x3) and R consists of: r1: p(a(x0),p(b(x1),p(a(x2),x3))) -> p(x2,p(a(a(x0)),p(b(x1),x3))) The estimated dependency graph contains the following SCCs: {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: p#(a(x0),p(b(x1),p(a(x2),x3))) -> p#(a(a(x0)),p(b(x1),x3)) and R consists of: r1: p(a(x0),p(b(x1),p(a(x2),x3))) -> p(x2,p(a(a(x0)),p(b(x1),x3))) The set of usable rules consists of (no rules) Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: p#_A(x1,x2) = ((0,1),(0,0)) x2 + (4,0) a_A(x1) = (9,1) p_A(x1,x2) = x2 + (5,2) b_A(x1) = (11,1) precedence: p# = a = p = b partial status: pi(p#) = [] pi(a) = [] pi(p) = [] pi(b) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.