YES We show the termination of the relative TRS R/S: R: minus(x,|0|()) -> x minus(s(x),s(y)) -> minus(x,y) f(|0|()) -> s(|0|()) f(s(x)) -> minus(s(x),g(f(x))) g(|0|()) -> |0|() g(s(x)) -> minus(s(x),f(g(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: minus#(s(x),s(y)) -> minus#(x,y) p2: f#(s(x)) -> minus#(s(x),g(f(x))) p3: f#(s(x)) -> g#(f(x)) p4: f#(s(x)) -> f#(x) p5: g#(s(x)) -> minus#(s(x),f(g(x))) p6: g#(s(x)) -> f#(g(x)) p7: g#(s(x)) -> g#(x) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: f(|0|()) -> s(|0|()) r4: f(s(x)) -> minus(s(x),g(f(x))) r5: g(|0|()) -> |0|() r6: g(s(x)) -> minus(s(x),f(g(x))) r7: rand(x) -> x r8: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p3, p4, p6, p7} {p1} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(s(x)) -> g#(x) p2: g#(s(x)) -> f#(g(x)) p3: f#(s(x)) -> f#(x) p4: f#(s(x)) -> g#(f(x)) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: f(|0|()) -> s(|0|()) r4: f(s(x)) -> minus(s(x),g(f(x))) r5: g(|0|()) -> |0|() r6: g(s(x)) -> minus(s(x),f(g(x))) r7: rand(x) -> x r8: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 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{1, x1} s_A(x1) = max{4, x1} f#_A(x1) = x1 g_A(x1) = max{2, x1} f_A(x1) = max{4, x1} minus_A(x1,x2) = x1 |0|_A = 3 rand_A(x1) = max{6, x1 + 1} precedence: s = f > f# > g# = g > minus = |0| = rand partial status: pi(g#) = [1] pi(s) = [1] pi(f#) = [1] pi(g) = [1] pi(f) = [1] pi(minus) = [1] pi(|0|) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: g#_A(x1) = max{3, x1} s_A(x1) = max{8, x1 + 6} f#_A(x1) = max{8, x1 - 5} g_A(x1) = x1 + 11 f_A(x1) = max{8, x1 + 1} minus_A(x1,x2) = max{9, x1 + 1} |0|_A = 1 rand_A(x1) = 0 precedence: g > g# > f# > f > s > minus = |0| = rand partial status: pi(g#) = [1] pi(s) = [1] pi(f#) = [] pi(g) = [] pi(f) = [1] pi(minus) = [1] pi(|0|) = [] pi(rand) = [] The next rules are strictly ordered: p1, p4 We remove them from the problem. -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: g#(s(x)) -> f#(g(x)) p2: f#(s(x)) -> f#(x) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: f(|0|()) -> s(|0|()) r4: f(s(x)) -> minus(s(x),g(f(x))) r5: g(|0|()) -> |0|() r6: g(s(x)) -> minus(s(x),f(g(x))) r7: rand(x) -> x r8: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p2} -- 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: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: f(|0|()) -> s(|0|()) r4: f(s(x)) -> minus(s(x),g(f(x))) r5: g(|0|()) -> |0|() r6: g(s(x)) -> minus(s(x),f(g(x))) r7: rand(x) -> x r8: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 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{1, x1} s_A(x1) = max{1, x1} minus_A(x1,x2) = max{x1 + 3, x2 - 8} |0|_A = 8 f_A(x1) = x1 + 8 g_A(x1) = max{6, x1 + 5} rand_A(x1) = max{4, x1 + 2} precedence: g > minus > f# = s > |0| = f > rand partial status: pi(f#) = [1] pi(s) = [1] pi(minus) = [1] pi(|0|) = [] pi(f) = [1] pi(g) = [1] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: f#_A(x1) = max{20, x1} s_A(x1) = max{31, x1 + 21} minus_A(x1,x2) = max{22, x1 + 4} |0|_A = 27 f_A(x1) = max{26, x1 + 2} g_A(x1) = max{18, x1 + 4} rand_A(x1) = 1 precedence: g > f# = s = minus = |0| = f = rand partial status: pi(f#) = [1] pi(s) = [] pi(minus) = [1] pi(|0|) = [] pi(f) = [1] pi(g) = [1] 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: minus#(s(x),s(y)) -> minus#(x,y) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: f(|0|()) -> s(|0|()) r4: f(s(x)) -> minus(s(x),g(f(x))) r5: g(|0|()) -> |0|() r6: g(s(x)) -> minus(s(x),f(g(x))) r7: rand(x) -> x r8: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: minus#_A(x1,x2) = max{x1 + 1, x2 + 1} s_A(x1) = max{5, x1} minus_A(x1,x2) = max{6, x1 + 1} |0|_A = 4 f_A(x1) = max{16, x1 + 9} g_A(x1) = x1 + 7 rand_A(x1) = max{12, x1 + 6} precedence: s > |0| = f > minus# = g > minus = rand partial status: pi(minus#) = [2] pi(s) = [1] pi(minus) = [1] pi(|0|) = [] pi(f) = [1] pi(g) = [1] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: minus#_A(x1,x2) = x2 s_A(x1) = max{23, x1 + 18} minus_A(x1,x2) = max{24, x1 + 2} |0|_A = 21 f_A(x1) = max{22, x1 + 9} g_A(x1) = max{9, x1 + 3} rand_A(x1) = 1 precedence: |0| > f > s > g > minus# = minus = rand partial status: pi(minus#) = [2] pi(s) = [] pi(minus) = [1] pi(|0|) = [] pi(f) = [1] pi(g) = [1] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.