YES We show the termination of the relative TRS R/S: R: f(|0|()) -> true() f(|1|()) -> false() f(s(x)) -> f(x) if(true(),s(x),s(y)) -> s(x) if(false(),s(x),s(y)) -> s(y) g(x,c(y)) -> c(g(x,y)) g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) 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#(s(x)) -> f#(x) p2: g#(x,c(y)) -> g#(x,y) p3: g#(x,c(y)) -> g#(x,if(f(x),c(g(s(x),y)),c(y))) p4: g#(x,c(y)) -> if#(f(x),c(g(s(x),y)),c(y)) p5: g#(x,c(y)) -> f#(x) p6: g#(x,c(y)) -> g#(s(x),y) and R consists of: r1: f(|0|()) -> true() r2: f(|1|()) -> false() r3: f(s(x)) -> f(x) r4: if(true(),s(x),s(y)) -> s(x) r5: if(false(),s(x),s(y)) -> s(y) r6: g(x,c(y)) -> c(g(x,y)) r7: g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) r8: rand(x) -> x r9: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p2, p6} {p1} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(x,c(y)) -> g#(s(x),y) p2: g#(x,c(y)) -> g#(x,y) and R consists of: r1: f(|0|()) -> true() r2: f(|1|()) -> false() r3: f(s(x)) -> f(x) r4: if(true(),s(x),s(y)) -> s(x) r5: if(false(),s(x),s(y)) -> s(y) r6: g(x,c(y)) -> c(g(x,y)) r7: g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) r8: rand(x) -> x r9: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1,x2) = max{1, x2 - 4} c_A(x1) = x1 + 6 s_A(x1) = x1 f_A(x1) = x1 |0|_A = 2 true_A = 1 |1|_A = 2 false_A = 1 if_A(x1,x2,x3) = max{x2, x3} g_A(x1,x2) = x2 rand_A(x1) = x1 + 2 precedence: true > s = f = if > g = rand > c = |1| = false > g# = |0| partial status: pi(g#) = [] pi(c) = [1] pi(s) = [1] pi(f) = [1] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [2, 3] pi(g) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1,x2) = 0 c_A(x1) = x1 + 21 s_A(x1) = max{19, x1 + 3} f_A(x1) = max{20, x1 + 18} |0|_A = 20 true_A = 21 |1|_A = 22 false_A = 21 if_A(x1,x2,x3) = max{17, x2 - 4, x3} g_A(x1,x2) = 0 rand_A(x1) = 1 precedence: g# = c = f = |0| = true > s = |1| = false = if = g = rand partial status: pi(g#) = [] pi(c) = [1] pi(s) = [] pi(f) = [] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [] pi(g) = [] pi(rand) = [] The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(x,c(y)) -> g#(s(x),y) and R consists of: r1: f(|0|()) -> true() r2: f(|1|()) -> false() r3: f(s(x)) -> f(x) r4: if(true(),s(x),s(y)) -> s(x) r5: if(false(),s(x),s(y)) -> s(y) r6: g(x,c(y)) -> c(g(x,y)) r7: g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) r8: rand(x) -> x r9: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(x,c(y)) -> g#(s(x),y) and R consists of: r1: f(|0|()) -> true() r2: f(|1|()) -> false() r3: f(s(x)) -> f(x) r4: if(true(),s(x),s(y)) -> s(x) r5: if(false(),s(x),s(y)) -> s(y) r6: g(x,c(y)) -> c(g(x,y)) r7: g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) r8: rand(x) -> x r9: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1,x2) = max{x1 + 2, x2 + 1} c_A(x1) = x1 + 3 s_A(x1) = 0 f_A(x1) = 2 |0|_A = 2 true_A = 1 |1|_A = 1 false_A = 0 if_A(x1,x2,x3) = max{2, x1 - 8, x3 - 1} g_A(x1,x2) = x2 + 10 rand_A(x1) = x1 precedence: g# = c = s = f = |0| = true = |1| = false = if = g = rand partial status: pi(g#) = [] pi(c) = [] pi(s) = [] pi(f) = [] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [] pi(g) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1,x2) = 0 c_A(x1) = max{1, x1} s_A(x1) = 0 f_A(x1) = 7 |0|_A = 0 true_A = 1 |1|_A = 0 false_A = 1 if_A(x1,x2,x3) = 3 g_A(x1,x2) = 1 rand_A(x1) = x1 + 2 precedence: g# = c = f = |0| = true = |1| = false = if = g = rand > s partial status: pi(g#) = [] pi(c) = [] pi(s) = [] pi(f) = [] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [] pi(g) = [] pi(rand) = [1] 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#(s(x)) -> f#(x) and R consists of: r1: f(|0|()) -> true() r2: f(|1|()) -> false() r3: f(s(x)) -> f(x) r4: if(true(),s(x),s(y)) -> s(x) r5: if(false(),s(x),s(y)) -> s(y) r6: g(x,c(y)) -> c(g(x,y)) r7: g(x,c(y)) -> g(x,if(f(x),c(g(s(x),y)),c(y))) r8: rand(x) -> x r9: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = x1 s_A(x1) = x1 f_A(x1) = max{3, x1 + 2} |0|_A = 3 true_A = 4 |1|_A = 5 false_A = 4 if_A(x1,x2,x3) = max{3, x1, x2 + 2, x3 + 1} g_A(x1,x2) = max{x1 + 27, x2 + 14} c_A(x1) = 11 rand_A(x1) = x1 + 2 precedence: s > f# = |0| = |1| = false = if = g > f = true > c = rand partial status: pi(f#) = [1] pi(s) = [1] pi(f) = [] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [1, 2, 3] pi(g) = [] pi(c) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = x1 + 5 s_A(x1) = x1 + 5 f_A(x1) = 6 |0|_A = 0 true_A = 7 |1|_A = 2 false_A = 7 if_A(x1,x2,x3) = max{4, x1 - 1, x2 + 2, x3 + 1} g_A(x1,x2) = 2 c_A(x1) = 3 rand_A(x1) = 1 precedence: f# = s = f = |0| = true = |1| = false = if = g = c = rand partial status: pi(f#) = [1] pi(s) = [1] pi(f) = [] pi(|0|) = [] pi(true) = [] pi(|1|) = [] pi(false) = [] pi(if) = [3] pi(g) = [] pi(c) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.