YES We show the termination of the TRS R: pred(s(x)) -> x minus(x,|0|()) -> x minus(x,s(y)) -> pred(minus(x,y)) quot(|0|(),s(y)) -> |0|() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) log(s(|0|())) -> |0|() log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: minus#(x,s(y)) -> pred#(minus(x,y)) p2: minus#(x,s(y)) -> minus#(x,y) p3: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) p4: quot#(s(x),s(y)) -> minus#(x,y) p5: log#(s(s(x))) -> log#(s(quot(x,s(s(|0|()))))) p6: log#(s(s(x))) -> quot#(x,s(s(|0|()))) and R consists of: r1: pred(s(x)) -> x r2: minus(x,|0|()) -> x r3: minus(x,s(y)) -> pred(minus(x,y)) r4: quot(|0|(),s(y)) -> |0|() r5: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r6: log(s(|0|())) -> |0|() r7: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The estimated dependency graph contains the following SCCs: {p5} {p3} {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: log#(s(s(x))) -> log#(s(quot(x,s(s(|0|()))))) and R consists of: r1: pred(s(x)) -> x r2: minus(x,|0|()) -> x r3: minus(x,s(y)) -> pred(minus(x,y)) r4: quot(|0|(),s(y)) -> |0|() r5: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r6: log(s(|0|())) -> |0|() r7: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The set of usable rules consists of r1, r2, r3, r4, r5 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: log#_A(x1) = max{9, x1 + 6} s_A(x1) = x1 + 14 quot_A(x1,x2) = x1 |0|_A = 8 pred_A(x1) = max{0, x1 - 1} minus_A(x1,x2) = x1 precedence: |0| = pred = minus > log# = quot > s partial status: pi(log#) = [1] pi(s) = [1] pi(quot) = [1] pi(|0|) = [] pi(pred) = [] pi(minus) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: log#_A(x1) = 1 s_A(x1) = max{5, x1} quot_A(x1,x2) = max{12, x1 + 7} |0|_A = 15 pred_A(x1) = 4 minus_A(x1,x2) = 5 precedence: pred > quot > |0| > s > log# = minus partial status: pi(log#) = [] pi(s) = [] pi(quot) = [] pi(|0|) = [] pi(pred) = [] pi(minus) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) and R consists of: r1: pred(s(x)) -> x r2: minus(x,|0|()) -> x r3: minus(x,s(y)) -> pred(minus(x,y)) r4: quot(|0|(),s(y)) -> |0|() r5: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r6: log(s(|0|())) -> |0|() r7: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: quot#_A(x1,x2) = max{4, x1 + 1} s_A(x1) = x1 + 6 minus_A(x1,x2) = max{2, x1 + 1} pred_A(x1) = x1 |0|_A = 0 precedence: quot# = s = minus = pred = |0| partial status: pi(quot#) = [] pi(s) = [] pi(minus) = [] pi(pred) = [] pi(|0|) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: quot#_A(x1,x2) = 0 s_A(x1) = x1 + 3 minus_A(x1,x2) = 1 pred_A(x1) = max{1, x1 - 1} |0|_A = 0 precedence: minus = pred > quot# = s = |0| partial status: pi(quot#) = [] pi(s) = [1] pi(minus) = [] pi(pred) = [] pi(|0|) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: minus#(x,s(y)) -> minus#(x,y) and R consists of: r1: pred(s(x)) -> x r2: minus(x,|0|()) -> x r3: minus(x,s(y)) -> pred(minus(x,y)) r4: quot(|0|(),s(y)) -> |0|() r5: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r6: log(s(|0|())) -> |0|() r7: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The set of usable rules consists of (no rules) 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{2, x1, x2 + 1} s_A(x1) = max{1, x1} precedence: minus# = s partial status: pi(minus#) = [1, 2] pi(s) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: minus#_A(x1,x2) = max{x1, x2 - 1} s_A(x1) = x1 precedence: minus# = s partial status: pi(minus#) = [1] pi(s) = [1] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.