YES We show the termination of the relative TRS R/S: R: f(g(x)) -> g(f(f(x))) f(h(x)) -> h(g(x)) |f'|(s(x),y,y) -> |f'|(y,x,s(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: f#(g(x)) -> f#(f(x)) p2: f#(g(x)) -> f#(x) p3: |f'|#(s(x),y,y) -> |f'|#(y,x,s(x)) and R consists of: r1: f(g(x)) -> g(f(f(x))) r2: f(h(x)) -> h(g(x)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) r4: rand(x) -> x r5: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p1, p2} {p3} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: f#(g(x)) -> f#(f(x)) p2: f#(g(x)) -> f#(x) and R consists of: r1: f(g(x)) -> g(f(f(x))) r2: f(h(x)) -> h(g(x)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) r4: rand(x) -> x r5: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: f#_A(x1) = ((0,0,0,0),(1,0,0,0),(1,1,0,0),(0,1,0,0)) x1 g_A(x1) = ((1,0,0,0),(1,1,0,0),(0,0,0,0),(1,1,0,0)) x1 + (1,1,1,2) f_A(x1) = x1 + (0,0,2,1) h_A(x1) = ((0,0,0,0),(0,0,0,0),(0,0,0,0),(1,0,0,0)) x1 + (1,1,1,1) |f'|_A(x1,x2,x3) = ((1,0,0,0),(0,1,0,0),(0,0,0,0),(1,0,1,0)) x1 + ((1,0,0,0),(1,1,0,0),(0,0,0,0),(0,0,0,0)) x2 + ((0,0,0,0),(0,0,0,0),(1,0,0,0),(1,1,0,0)) x3 s_A(x1) = ((1,0,0,0),(1,1,0,0),(1,1,1,0),(1,1,1,1)) x1 + (0,1,2,1) rand_A(x1) = x1 + (1,1,1,1) 2. lexicographic path order with precedence: precedence: f > h > |f'| > s > g > rand > f# argument filter: pi(f#) = [] pi(g) = [] pi(f) = [] pi(h) = [] pi(|f'|) = [] pi(s) = [] pi(rand) = [] The next rules are strictly ordered: p1, p2 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'|#(s(x),y,y) -> |f'|#(y,x,s(x)) and R consists of: r1: f(g(x)) -> g(f(f(x))) r2: f(h(x)) -> h(g(x)) r3: |f'|(s(x),y,y) -> |f'|(y,x,s(x)) r4: rand(x) -> x r5: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: |f'|#_A(x1,x2,x3) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(1,1,1,1)) x1 + x2 + ((0,0,0,0),(1,0,0,0),(0,0,0,0),(0,1,0,0)) x3 s_A(x1) = ((1,0,0,0),(1,1,0,0),(0,1,1,0),(1,0,1,1)) x1 + (0,2,1,2) f_A(x1) = ((0,0,0,0),(1,0,0,0),(0,1,0,0),(1,0,0,0)) x1 + (3,4,4,11) g_A(x1) = ((0,0,0,0),(1,0,0,0),(1,0,0,0),(1,1,0,0)) x1 + (1,1,1,1) h_A(x1) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,1,1)) x1 + (1,0,4,11) |f'|_A(x1,x2,x3) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,1,0,1)) x1 + x2 + ((0,0,0,0),(1,0,0,0),(0,1,0,0),(0,1,1,0)) x3 rand_A(x1) = x1 + (1,0,1,1) 2. lexicographic path order with precedence: precedence: |f'| > s > rand > f > g > h > |f'|# argument filter: pi(|f'|#) = [1, 2] pi(s) = 1 pi(f) = [] pi(g) = [] pi(h) = [] pi(|f'|) = 2 pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.