YES We show the termination of the TRS R: le(|0|(),y) -> true() le(s(x),|0|()) -> false() le(s(x),s(y)) -> le(x,y) minus(|0|(),y) -> |0|() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> |0|() if_minus(false(),s(x),y) -> s(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: le#(s(x),s(y)) -> le#(x,y) p2: minus#(s(x),y) -> if_minus#(le(s(x),y),s(x),y) p3: minus#(s(x),y) -> le#(s(x),y) p4: if_minus#(false(),s(x),y) -> minus#(x,y) p5: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) p6: quot#(s(x),s(y)) -> minus#(x,y) p7: log#(s(s(x))) -> log#(s(quot(x,s(s(|0|()))))) p8: log#(s(s(x))) -> quot#(x,s(s(|0|()))) 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: minus(|0|(),y) -> |0|() r5: minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) r6: if_minus(true(),s(x),y) -> |0|() r7: if_minus(false(),s(x),y) -> s(minus(x,y)) r8: quot(|0|(),s(y)) -> |0|() r9: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r10: log(s(|0|())) -> |0|() r11: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The estimated dependency graph contains the following SCCs: {p7} {p5} {p2, p4} {p1} -- 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: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(|0|(),y) -> |0|() r5: minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) r6: if_minus(true(),s(x),y) -> |0|() r7: if_minus(false(),s(x),y) -> s(minus(x,y)) r8: quot(|0|(),s(y)) -> |0|() r9: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r10: log(s(|0|())) -> |0|() r11: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 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{21, x1 + 7} s_A(x1) = max{13, x1 + 11} quot_A(x1,x2) = x1 + 3 |0|_A = 6 le_A(x1,x2) = 6 true_A = 1 false_A = 5 if_minus_A(x1,x2,x3) = max{10, x2} minus_A(x1,x2) = max{2, x1} precedence: quot = le = true > |0| = false = minus > log# = s = if_minus partial status: pi(log#) = [1] pi(s) = [] pi(quot) = [] pi(|0|) = [] pi(le) = [] pi(true) = [] pi(false) = [] pi(if_minus) = [2] pi(minus) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: log#_A(x1) = 54 s_A(x1) = 54 quot_A(x1,x2) = 54 |0|_A = 33 le_A(x1,x2) = 74 true_A = 35 false_A = 55 if_minus_A(x1,x2,x3) = max{32, x2 - 16} minus_A(x1,x2) = 53 precedence: quot > log# = s > false = minus > |0| = le = true = if_minus partial status: pi(log#) = [] pi(s) = [] pi(quot) = [] pi(|0|) = [] pi(le) = [] pi(true) = [] pi(false) = [] pi(if_minus) = [] 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: le(|0|(),y) -> true() r2: le(s(x),|0|()) -> false() r3: le(s(x),s(y)) -> le(x,y) r4: minus(|0|(),y) -> |0|() r5: minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) r6: if_minus(true(),s(x),y) -> |0|() r7: if_minus(false(),s(x),y) -> s(minus(x,y)) r8: quot(|0|(),s(y)) -> |0|() r9: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r10: log(s(|0|())) -> |0|() r11: log(s(s(x))) -> s(log(s(quot(x,s(s(|0|())))))) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7 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) = x1 + 2 s_A(x1) = x1 + 13 minus_A(x1,x2) = x1 + 5 le_A(x1,x2) = max{x1 + 8, x2 + 13} |0|_A = 11 true_A = 12 false_A = 12 if_minus_A(x1,x2,x3) = max{9, x2 + 5} precedence: quot# = minus = |0| > le = true = false = if_minus > s partial status: pi(quot#) = [1] pi(s) = [1] pi(minus) = [1] pi(le) = [1, 2] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(if_minus) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: quot#_A(x1,x2) = max{0, x1 - 9} s_A(x1) = max{9, x1 + 4} minus_A(x1,x2) = x1 + 4 le_A(x1,x2) = max{x1 + 14, x2 - 5} |0|_A = 2 true_A = 15 false_A = 3 if_minus_A(x1,x2,x3) = 0 precedence: quot# = s = minus = le = |0| = true = false = if_minus partial status: pi(quot#) = [] pi(s) = [1] pi(minus) = [1] pi(le) = [1] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(if_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: if_minus#(false(),s(x),y) -> minus#(x,y) p2: minus#(s(x),y) -> if_minus#(le(s(x),y),s(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: minus(|0|(),y) -> |0|() r5: minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) r6: if_minus(true(),s(x),y) -> |0|() r7: if_minus(false(),s(x),y) -> s(minus(x,y)) r8: quot(|0|(),s(y)) -> |0|() r9: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r10: log(s(|0|())) -> |0|() r11: 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: if_minus#_A(x1,x2,x3) = max{x1 + 2, x2 + 1, x3 + 4} false_A = 4 s_A(x1) = x1 + 5 minus#_A(x1,x2) = max{x1 + 6, x2 + 4} le_A(x1,x2) = max{x1 + 3, x2 - 6} |0|_A = 11 true_A = 12 precedence: if_minus# = s = minus# = le = |0| > false = true partial status: pi(if_minus#) = [2] pi(false) = [] pi(s) = [1] pi(minus#) = [1] pi(le) = [] pi(|0|) = [] pi(true) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: if_minus#_A(x1,x2,x3) = max{1, x2} false_A = 7 s_A(x1) = x1 + 8 minus#_A(x1,x2) = x1 le_A(x1,x2) = 1 |0|_A = 0 true_A = 2 precedence: true > if_minus# = false = s = minus# = le = |0| partial status: pi(if_minus#) = [] pi(false) = [] pi(s) = [1] pi(minus#) = [1] pi(le) = [] pi(|0|) = [] pi(true) = [] The next rules are strictly ordered: p1, p2 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: 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: minus(|0|(),y) -> |0|() r5: minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) r6: if_minus(true(),s(x),y) -> |0|() r7: if_minus(false(),s(x),y) -> s(minus(x,y)) r8: quot(|0|(),s(y)) -> |0|() r9: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r10: log(s(|0|())) -> |0|() r11: 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: le#_A(x1,x2) = max{2, x1 - 1, x2 + 1} s_A(x1) = max{1, x1} precedence: le# = s partial status: pi(le#) = [2] pi(s) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: le#_A(x1,x2) = 0 s_A(x1) = max{2, x1} precedence: le# = s partial status: pi(le#) = [] pi(s) = [1] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.