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. matrix interpretations: carrier: N^2 order: lexicographic order interpretations: if_mod#_A(x1,x2,x3) = x2 + ((1,0),(1,1)) x3 true_A() = (1,1) s_A(x1) = ((1,0),(1,1)) x1 + (0,3) mod#_A(x1,x2) = ((1,0),(1,1)) x1 + ((1,0),(1,1)) x2 + (0,1) minus_A(x1,x2) = x1 + (0,1) le_A(x1,x2) = x1 + ((0,0),(1,0)) x2 + (2,2) |0|_A() = (1,0) false_A() = (1,7) pred_A(x1) = x1 mod_A(x1,x2) = x1 + ((0,0),(1,0)) x2 + (2,2) if_mod_A(x1,x2,x3) = x2 + ((0,0),(1,0)) x3 + (2,1) rand_A(x1) = x1 + (1,1) 2. lexicographic path order with precedence: precedence: s > rand > if_mod > true > |0| > le > mod > pred > false > minus > mod# > if_mod# argument filter: pi(if_mod#) = 2 pi(true) = [] pi(s) = [] pi(mod#) = 1 pi(minus) = [] pi(le) = 1 pi(|0|) = [] pi(false) = [] pi(pred) = 1 pi(mod) = [1] pi(if_mod) = 2 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: 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. matrix interpretations: carrier: N^2 order: lexicographic order interpretations: le#_A(x1,x2) = x1 + ((1,0),(1,1)) x2 s_A(x1) = x1 + (0,3) le_A(x1,x2) = x1 + ((0,0),(1,0)) x2 + (2,1) |0|_A() = (1,6) true_A() = (1,8) false_A() = (1,1) pred_A(x1) = x1 minus_A(x1,x2) = x1 + (0,1) mod_A(x1,x2) = x1 + x2 + (1,2) if_mod_A(x1,x2,x3) = x2 + x3 + (1,1) rand_A(x1) = ((1,0),(1,0)) x1 + (1,1) 2. lexicographic path order with precedence: precedence: rand > mod > minus > if_mod > pred > |0| > s > true > le > false > le# argument filter: pi(le#) = [2] pi(s) = [1] pi(le) = [1] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = 1 pi(minus) = 1 pi(mod) = 1 pi(if_mod) = 2 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. matrix interpretations: carrier: N^2 order: lexicographic order interpretations: minus#_A(x1,x2) = x1 + ((1,0),(1,1)) x2 s_A(x1) = x1 + (0,3) le_A(x1,x2) = x1 + ((0,0),(1,0)) x2 + (2,1) |0|_A() = (1,1) true_A() = (1,1) false_A() = (1,1) pred_A(x1) = x1 minus_A(x1,x2) = x1 + (0,1) mod_A(x1,x2) = x1 + ((0,0),(1,0)) x2 + (2,2) if_mod_A(x1,x2,x3) = x2 + ((0,0),(1,0)) x3 + (2,1) rand_A(x1) = ((1,0),(1,0)) x1 + (1,1) 2. lexicographic path order with precedence: precedence: rand > minus > |0| > true > s > if_mod > mod > le > pred > false > minus# argument filter: pi(minus#) = 2 pi(s) = [1] pi(le) = [1] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(pred) = 1 pi(minus) = 1 pi(mod) = [1] pi(if_mod) = 2 pi(rand) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.