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. lexicographic path order with precedence: precedence: quot > log# > le > if_minus > s > |0| > false > minus > true argument filter: pi(log#) = [1] pi(s) = [1] pi(quot) = 1 pi(|0|) = [] pi(le) = 1 pi(true) = [] pi(false) = [] pi(if_minus) = 2 pi(minus) = 1 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: log#_A(x1) = x1 s_A(x1) = (1,2,1) quot_A(x1,x2) = ((0,0,0),(0,0,0),(1,0,0)) x1 + (2,1,1) |0|_A() = (1,2,3) le_A(x1,x2) = ((1,0,0),(0,1,0),(1,1,1)) x1 true_A() = (0,0,0) false_A() = (1,1,1) if_minus_A(x1,x2,x3) = (2,3,5) minus_A(x1,x2) = (3,4,4) 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. lexicographic path order with precedence: precedence: minus > if_minus > s > quot# > |0| > le > true > false argument filter: pi(quot#) = [1, 2] pi(s) = [1] pi(minus) = 1 pi(le) = [1] pi(|0|) = [] pi(true) = [] pi(false) = [] pi(if_minus) = 2 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: quot#_A(x1,x2) = ((1,0,0),(0,1,0),(1,1,0)) x1 s_A(x1) = ((0,0,0),(1,0,0),(0,0,0)) x1 + (1,1,1) minus_A(x1,x2) = ((0,0,0),(0,0,0),(1,0,0)) x1 + (3,6,1) le_A(x1,x2) = x1 + (0,0,1) |0|_A() = (1,1,0) true_A() = (0,0,0) false_A() = (1,1,1) if_minus_A(x1,x2,x3) = (2,5,3) 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. lexicographic path order with precedence: precedence: le > if_minus# > minus# > true > false > |0| > s argument filter: pi(if_minus#) = 2 pi(false) = [] pi(s) = [1] pi(minus#) = 1 pi(le) = [] pi(|0|) = [] pi(true) = [] 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: if_minus#_A(x1,x2,x3) = ((1,0,0),(1,0,0),(0,0,0)) x2 + (0,0,1) false_A() = (1,1,1) s_A(x1) = ((1,0,0),(1,0,0),(0,0,0)) x1 + (1,1,1) minus#_A(x1,x2) = x1 + (2,0,0) le_A(x1,x2) = (1,1,1) |0|_A() = (0,0,0) true_A() = (0,0,0) 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 monotone reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: s > le# argument filter: pi(le#) = [1, 2] pi(s) = 1 2. matrix interpretations: carrier: N^3 order: lexicographic order interpretations: le#_A(x1,x2) = ((1,0,0),(1,1,0),(1,1,1)) x1 + ((1,0,0),(1,1,0),(1,1,1)) x2 s_A(x1) = ((1,0,0),(1,1,0),(1,1,1)) x1 + (1,1,1) The next rules are strictly ordered: p1 r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11 We remove them from the problem. Then no dependency pair remains.