YES We show the termination of the relative TRS R/S: R: g(c(x,s(y))) -> g(c(s(x),y)) f(c(s(x),y)) -> f(c(x,s(y))) f(f(x)) -> f(d(f(x))) f(x) -> x S: rand(x) -> x rand(x) -> rand(s(x)) -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(c(x,s(y))) -> g#(c(s(x),y)) p2: f#(c(s(x),y)) -> f#(c(x,s(y))) p3: f#(f(x)) -> f#(d(f(x))) and R consists of: r1: g(c(x,s(y))) -> g(c(s(x),y)) r2: f(c(s(x),y)) -> f(c(x,s(y))) r3: f(f(x)) -> f(d(f(x))) r4: f(x) -> x r5: rand(x) -> x r6: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p1} {p2} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(c(x,s(y))) -> g#(c(s(x),y)) and R consists of: r1: g(c(x,s(y))) -> g(c(s(x),y)) r2: f(c(s(x),y)) -> f(c(x,s(y))) r3: f(f(x)) -> f(d(f(x))) r4: f(x) -> x r5: rand(x) -> x r6: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1) = max{9, x1} c_A(x1,x2) = max{x1 + 10, x2 + 12} s_A(x1) = x1 g_A(x1) = max{11, x1} f_A(x1) = max{5, x1 + 3} d_A(x1) = max{4, x1} rand_A(x1) = max{2, x1 + 1} precedence: s = f > c > g# = g = d > rand partial status: pi(g#) = [1] pi(c) = [2] pi(s) = [1] pi(g) = [1] pi(f) = [] pi(d) = [1] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1) = x1 + 3 c_A(x1,x2) = x2 + 7 s_A(x1) = max{13, x1 + 4} g_A(x1) = max{40, x1 + 20} f_A(x1) = 9 d_A(x1) = max{15, x1 + 6} rand_A(x1) = 2 precedence: s = f = d > g# = c = g = rand partial status: pi(g#) = [1] pi(c) = [2] pi(s) = [] pi(g) = [1] pi(f) = [] pi(d) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: f#(c(s(x),y)) -> f#(c(x,s(y))) and R consists of: r1: g(c(x,s(y))) -> g(c(s(x),y)) r2: f(c(s(x),y)) -> f(c(x,s(y))) r3: f(f(x)) -> f(d(f(x))) r4: f(x) -> x r5: rand(x) -> x r6: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = max{2, x1} c_A(x1,x2) = max{x1 + 6, x2 + 6} s_A(x1) = max{3, x1} g_A(x1) = max{10, x1 + 5} f_A(x1) = x1 + 10 d_A(x1) = max{0, x1 - 11} rand_A(x1) = max{8, x1 + 4} precedence: c = s > f# > g > f > d = rand partial status: pi(f#) = [1] pi(c) = [1, 2] pi(s) = [1] pi(g) = [] pi(f) = [1] pi(d) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = 1 c_A(x1,x2) = max{x1 + 12, x2 + 6} s_A(x1) = max{5, x1} g_A(x1) = 13 f_A(x1) = x1 + 19 d_A(x1) = 1 rand_A(x1) = 1 precedence: f = d > f# = c = s = g = rand partial status: pi(f#) = [] pi(c) = [1] pi(s) = [1] pi(g) = [] pi(f) = [1] pi(d) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.