YES We show the termination of the TRS R: f(c(a(),z,x)) -> b(a(),z) b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) b(y,z) -> z -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(a(),z,x)) -> b#(a(),z) p2: b#(x,b(z,y)) -> f#(b(f(f(z)),c(x,z,y))) p3: b#(x,b(z,y)) -> b#(f(f(z)),c(x,z,y)) p4: b#(x,b(z,y)) -> f#(f(z)) p5: b#(x,b(z,y)) -> f#(z) and R consists of: r1: f(c(a(),z,x)) -> b(a(),z) r2: b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) r3: b(y,z) -> z The estimated dependency graph contains the following SCCs: {p1, p2, p4, p5} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(a(),z,x)) -> b#(a(),z) p2: b#(x,b(z,y)) -> f#(z) p3: b#(x,b(z,y)) -> f#(f(z)) p4: b#(x,b(z,y)) -> f#(b(f(f(z)),c(x,z,y))) and R consists of: r1: f(c(a(),z,x)) -> b(a(),z) r2: b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) r3: b(y,z) -> z The set of usable rules consists of r1, r2, r3 Take the reduction pair: max/plus interpretations on natural numbers: f#_A(x1) = x1 + 2 c_A(x1,x2,x3) = max{x1 + 1, x2 + 1, x3 + 1} a_A = 0 b#_A(x1,x2) = max{x1 + 3, x2 + 3} b_A(x1,x2) = max{x1, x2} f_A(x1) = max{0, x1 - 1} The next rules are strictly ordered: p2, p3 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(a(),z,x)) -> b#(a(),z) p2: b#(x,b(z,y)) -> f#(b(f(f(z)),c(x,z,y))) and R consists of: r1: f(c(a(),z,x)) -> b(a(),z) r2: b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) r3: b(y,z) -> z 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(a(),z,x)) -> b#(a(),z) p2: b#(x,b(z,y)) -> f#(b(f(f(z)),c(x,z,y))) and R consists of: r1: f(c(a(),z,x)) -> b(a(),z) r2: b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) r3: b(y,z) -> z The set of usable rules consists of r1, r2, r3 Take the reduction pair: max/plus interpretations on natural numbers: f#_A(x1) = max{7, x1 - 6} c_A(x1,x2,x3) = x2 + 14 a_A = 2 b#_A(x1,x2) = max{x1 + 6, x2 + 8} b_A(x1,x2) = max{7, x1 + 4, x2} f_A(x1) = max{7, x1 - 10} The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(a(),z,x)) -> b#(a(),z) and R consists of: r1: f(c(a(),z,x)) -> b(a(),z) r2: b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) r3: b(y,z) -> z The estimated dependency graph contains the following SCCs: (no SCCs)