YES We show the termination of the relative TRS R/S: R: le(|0|(),y) -> true() le(s(x),|0|()) -> false() le(s(x),s(y)) -> le(x,y) pred(s(x)) -> x minus(x,|0|()) -> x minus(x,s(y)) -> pred(minus(x,y)) mod(|0|(),y) -> |0|() mod(s(x),|0|()) -> |0|() mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) if_mod(false(),s(x),s(y)) -> 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: le#(s(x),s(y)) -> le#(x,y) p2: minus#(x,s(y)) -> pred#(minus(x,y)) p3: minus#(x,s(y)) -> minus#(x,y) p4: mod#(s(x),s(y)) -> if_mod#(le(y,x),s(x),s(y)) p5: mod#(s(x),s(y)) -> le#(y,x) p6: if_mod#(true(),s(x),s(y)) -> mod#(minus(x,y),s(y)) p7: if_mod#(true(),s(x),s(y)) -> minus#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: pred(s(x)) -> x r5: minus(x,|0|()) -> x r6: minus(x,s(y)) -> pred(minus(x,y)) r7: mod(|0|(),y) -> |0|() r8: mod(s(x),|0|()) -> |0|() r9: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r10: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r11: if_mod(false(),s(x),s(y)) -> s(x) r12: rand(x) -> x r13: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p4, p6} {p1} {p3} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: if_mod#(true(),s(x),s(y)) -> mod#(minus(x,y),s(y)) p2: mod#(s(x),s(y)) -> if_mod#(le(y,x),s(x),s(y)) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: pred(s(x)) -> x r5: minus(x,|0|()) -> x r6: minus(x,s(y)) -> pred(minus(x,y)) r7: mod(|0|(),y) -> |0|() r8: mod(s(x),|0|()) -> |0|() r9: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r10: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r11: if_mod(false(),s(x),s(y)) -> s(x) r12: rand(x) -> x r13: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: if_mod#_A(x1,x2,x3) = ((1,0),(0,0)) x1 + x2 + ((1,0),(1,0)) x3 + (1,2) true_A() = (2,1) s_A(x1) = ((1,1),(0,0)) x1 mod#_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(1,0)) x2 + (3,2) minus_A(x1,x2) = ((1,0),(1,1)) x1 + (0,3) le_A(x1,x2) = ((0,0),(1,1)) x1 + (2,4) |0|_A() = (3,1) false_A() = (1,1) pred_A(x1) = ((1,0),(1,0)) x1 + (0,1) mod_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(1,0)) x2 + (1,3) if_mod_A(x1,x2,x3) = ((1,0),(0,0)) x2 + ((1,0),(1,1)) x3 + (1,3) rand_A(x1) = ((1,1),(0,1)) x1 + (1,1) precedence: if_mod# = true = s = mod# = minus = le = |0| = false = pred = mod = if_mod = rand partial status: pi(if_mod#) = [] pi(true) = [] pi(s) = [] pi(mod#) = [] pi(minus) = [] pi(le) = [] pi(|0|) = [] pi(false) = [] pi(pred) = [] pi(mod) = [] pi(if_mod) = [] pi(rand) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: if_mod#_A(x1,x2,x3) = ((1,0),(0,0)) x1 + ((0,1),(0,0)) x2 + ((0,1),(0,1)) x3 + (1,1) true_A() = (9,1) s_A(x1) = ((1,1),(1,1)) x1 + (20,4) mod#_A(x1,x2) = ((1,1),(0,0)) x1 + ((0,1),(0,1)) x2 + (1,1) minus_A(x1,x2) = x1 + (1,2) le_A(x1,x2) = (10,1) |0|_A() = (0,1) false_A() = (20,5) pred_A(x1) = x1 mod_A(x1,x2) = ((0,1),(0,1)) x1 + ((0,0),(0,1)) x2 + (19,0) if_mod_A(x1,x2,x3) = ((0,1),(0,1)) x2 + ((0,0),(0,1)) x3 + (18,0) rand_A(x1) = (21,4) precedence: mod# > le = mod = if_mod > |0| > false > s = minus > pred > if_mod# = true = rand partial status: pi(if_mod#) = [] pi(true) = [] pi(s) = [] pi(mod#) = [] pi(minus) = [1] pi(le) = [] pi(|0|) = [] pi(false) = [] pi(pred) = [] pi(mod) = [] pi(if_mod) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: mod#(s(x),s(y)) -> if_mod#(le(y,x),s(x),s(y)) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: pred(s(x)) -> x r5: minus(x,|0|()) -> x r6: minus(x,s(y)) -> pred(minus(x,y)) r7: mod(|0|(),y) -> |0|() r8: mod(s(x),|0|()) -> |0|() r9: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r10: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r11: if_mod(false(),s(x),s(y)) -> s(x) r12: rand(x) -> x r13: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: (no SCCs) -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: le#(s(x),s(y)) -> le#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: pred(s(x)) -> x r5: minus(x,|0|()) -> x r6: minus(x,s(y)) -> pred(minus(x,y)) r7: mod(|0|(),y) -> |0|() r8: mod(s(x),|0|()) -> |0|() r9: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r10: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r11: if_mod(false(),s(x),s(y)) -> s(x) r12: rand(x) -> x r13: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: le#_A(x1,x2) = max{11, x1 + 1} s_A(x1) = max{10, x1} le_A(x1,x2) = x1 + 11 |0|_A = 4 true_A = 3 false_A = 0 pred_A(x1) = max{1, x1} minus_A(x1,x2) = max{3, x1, x2 + 2} mod_A(x1,x2) = max{x1 + 5, x2 + 9} if_mod_A(x1,x2,x3) = max{x1 - 2, x2 + 5, x3 + 9} rand_A(x1) = max{21, x1 + 11} precedence: minus > le# = pred = mod = if_mod > |0| > s = le = true > false = rand partial status: pi(le#) = [1] pi(s) = [1] pi(le) = [1] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = [1] pi(minus) = [1, 2] pi(mod) = [] pi(if_mod) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: le#_A(x1,x2) = max{0, x1 - 1} s_A(x1) = x1 le_A(x1,x2) = x1 + 5 |0|_A = 0 true_A = 0 false_A = 2 pred_A(x1) = max{5, x1} minus_A(x1,x2) = max{x1 + 5, x2 + 5} mod_A(x1,x2) = 0 if_mod_A(x1,x2,x3) = 0 rand_A(x1) = 1 precedence: false = minus > |0| = true = pred > le# = s = le = mod = if_mod = rand partial status: pi(le#) = [] pi(s) = [1] pi(le) = [] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = [1] pi(minus) = [1, 2] pi(mod) = [] pi(if_mod) = [] 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#(x,s(y)) -> minus#(x,y) and R consists of: r1: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: pred(s(x)) -> x r5: minus(x,|0|()) -> x r6: minus(x,s(y)) -> pred(minus(x,y)) r7: mod(|0|(),y) -> |0|() r8: mod(s(x),|0|()) -> |0|() r9: mod(s(x),s(y)) -> if_mod(le(y,x),s(x),s(y)) r10: if_mod(true(),s(x),s(y)) -> mod(minus(x,y),s(y)) r11: if_mod(false(),s(x),s(y)) -> s(x) r12: rand(x) -> x r13: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13 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{3, x2 + 1} s_A(x1) = max{2, x1} le_A(x1,x2) = max{x1 + 7, x2 + 4} |0|_A = 12 true_A = 11 false_A = 8 pred_A(x1) = x1 minus_A(x1,x2) = max{x1, x2 + 1} mod_A(x1,x2) = max{8, x1 + 3, x2 + 6} if_mod_A(x1,x2,x3) = max{8, x2 + 3, x3 + 6} rand_A(x1) = max{6, x1 + 3} precedence: minus# = false > minus > true = pred = mod = if_mod > |0| > s = le > rand partial status: pi(minus#) = [2] pi(s) = [1] pi(le) = [1, 2] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = [1] pi(minus) = [1, 2] pi(mod) = [] pi(if_mod) = [] pi(rand) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: minus#_A(x1,x2) = max{19, x2} s_A(x1) = max{19, x1 + 7} le_A(x1,x2) = max{x1 - 8, x2 + 6} |0|_A = 1 true_A = 2 false_A = 6 pred_A(x1) = max{23, x1} minus_A(x1,x2) = max{x1 + 24, x2 + 17} mod_A(x1,x2) = 0 if_mod_A(x1,x2,x3) = 0 rand_A(x1) = 1 precedence: mod = if_mod > minus# = s = le = |0| = true = false = pred = minus = rand partial status: pi(minus#) = [2] pi(s) = [1] pi(le) = [2] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = [] pi(minus) = [1, 2] pi(mod) = [] pi(if_mod) = [] pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.