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: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: g#_A(x1) = x1 + (0,1) c_A(x1,x2) = x2 + (1,3) s_A(x1) = ((1,0),(1,1)) x1 + (0,5) g_A(x1) = (0,0) f_A(x1) = ((1,0),(0,0)) x1 + (1,2) d_A(x1) = ((0,0),(1,0)) x1 + (1,0) rand_A(x1) = ((1,0),(0,0)) x1 + (1,1) precedence: g# = c = s = g = f = d = rand partial status: pi(g#) = [] pi(c) = [] pi(s) = [] pi(g) = [] pi(f) = [] pi(d) = [] pi(rand) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: g#_A(x1) = ((1,0),(1,0)) x1 c_A(x1,x2) = ((1,0),(0,0)) x2 + (1,5) s_A(x1) = (2,4) g_A(x1) = (0,0) f_A(x1) = (4,6) d_A(x1) = (0,0) rand_A(x1) = (0,0) precedence: rand > c = s = f = d > g# = g partial status: pi(g#) = [] pi(c) = [] pi(s) = [] pi(g) = [] 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: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: f#_A(x1) = ((1,0),(1,1)) x1 + (1,1) c_A(x1,x2) = x1 + (1,4) s_A(x1) = x1 + (0,3) g_A(x1) = (0,0) f_A(x1) = x1 + (1,4) d_A(x1) = (0,0) rand_A(x1) = ((1,0),(0,0)) x1 + (1,1) precedence: f# = c = f > s > g > d = rand partial status: pi(f#) = [] pi(c) = [1] pi(s) = [1] pi(g) = [] pi(f) = [1] pi(d) = [] pi(rand) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: f#_A(x1) = (0,0) c_A(x1,x2) = ((1,0),(1,1)) x1 + (4,4) s_A(x1) = x1 + (3,3) g_A(x1) = (0,0) f_A(x1) = (2,2) d_A(x1) = (1,1) rand_A(x1) = (0,0) precedence: f# > c > rand > s = g = f = d partial status: pi(f#) = [] pi(c) = [] pi(s) = [1] pi(g) = [] pi(f) = [] pi(d) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.