YES We show the termination of the TRS R: nonZero(|0|()) -> false() nonZero(s(x)) -> true() p(s(|0|())) -> |0|() p(s(s(x))) -> s(p(s(x))) id_inc(x) -> x id_inc(x) -> s(x) random(x) -> rand(x,|0|()) rand(x,y) -> if(nonZero(x),x,y) if(false(),x,y) -> y if(true(),x,y) -> rand(p(x),id_inc(y)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: p#(s(s(x))) -> p#(s(x)) p2: random#(x) -> rand#(x,|0|()) p3: rand#(x,y) -> if#(nonZero(x),x,y) p4: rand#(x,y) -> nonZero#(x) p5: if#(true(),x,y) -> rand#(p(x),id_inc(y)) p6: if#(true(),x,y) -> p#(x) p7: if#(true(),x,y) -> id_inc#(y) and R consists of: r1: nonZero(|0|()) -> false() r2: nonZero(s(x)) -> true() r3: p(s(|0|())) -> |0|() r4: p(s(s(x))) -> s(p(s(x))) r5: id_inc(x) -> x r6: id_inc(x) -> s(x) r7: random(x) -> rand(x,|0|()) r8: rand(x,y) -> if(nonZero(x),x,y) r9: if(false(),x,y) -> y r10: if(true(),x,y) -> rand(p(x),id_inc(y)) The estimated dependency graph contains the following SCCs: {p3, p5} {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: rand#(x,y) -> if#(nonZero(x),x,y) p2: if#(true(),x,y) -> rand#(p(x),id_inc(y)) and R consists of: r1: nonZero(|0|()) -> false() r2: nonZero(s(x)) -> true() r3: p(s(|0|())) -> |0|() r4: p(s(s(x))) -> s(p(s(x))) r5: id_inc(x) -> x r6: id_inc(x) -> s(x) r7: random(x) -> rand(x,|0|()) r8: rand(x,y) -> if(nonZero(x),x,y) r9: if(false(),x,y) -> y r10: if(true(),x,y) -> rand(p(x),id_inc(y)) The set of usable rules consists of r1, r2, r3, r4, r5, r6 Take the reduction pair: max/plus interpretations on natural numbers: rand#_A(x1,x2) = max{0, x1 - 4} if#_A(x1,x2,x3) = max{0, x1 - 5, x2 - 4} nonZero_A(x1) = x1 true_A = 8 p_A(x1) = max{2, x1 - 2} id_inc_A(x1) = max{8, x1 + 4} |0|_A = 3 false_A = 1 s_A(x1) = max{8, x1 + 4} The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: rand#(x,y) -> if#(nonZero(x),x,y) and R consists of: r1: nonZero(|0|()) -> false() r2: nonZero(s(x)) -> true() r3: p(s(|0|())) -> |0|() r4: p(s(s(x))) -> s(p(s(x))) r5: id_inc(x) -> x r6: id_inc(x) -> s(x) r7: random(x) -> rand(x,|0|()) r8: rand(x,y) -> if(nonZero(x),x,y) r9: if(false(),x,y) -> y r10: if(true(),x,y) -> rand(p(x),id_inc(y)) The estimated dependency graph contains the following SCCs: (no SCCs) -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: p#(s(s(x))) -> p#(s(x)) and R consists of: r1: nonZero(|0|()) -> false() r2: nonZero(s(x)) -> true() r3: p(s(|0|())) -> |0|() r4: p(s(s(x))) -> s(p(s(x))) r5: id_inc(x) -> x r6: id_inc(x) -> s(x) r7: random(x) -> rand(x,|0|()) r8: rand(x,y) -> if(nonZero(x),x,y) r9: if(false(),x,y) -> y r10: if(true(),x,y) -> rand(p(x),id_inc(y)) The set of usable rules consists of (no rules) Take the reduction pair: max/plus interpretations on natural numbers: p#_A(x1) = max{0, x1 - 1} s_A(x1) = x1 + 2 The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.