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)) gcd(|0|(),y) -> y gcd(s(x),|0|()) -> s(x) gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) -- 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: gcd#(s(x),s(y)) -> if_gcd#(le(y,x),s(x),s(y)) p6: gcd#(s(x),s(y)) -> le#(y,x) p7: if_gcd#(true(),s(x),s(y)) -> gcd#(minus(x,y),s(y)) p8: if_gcd#(true(),s(x),s(y)) -> minus#(x,y) p9: if_gcd#(false(),s(x),s(y)) -> gcd#(minus(y,x),s(x)) p10: if_gcd#(false(),s(x),s(y)) -> minus#(y,x) 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: gcd(|0|(),y) -> y r9: gcd(s(x),|0|()) -> s(x) r10: gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) r11: if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) r12: if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) The estimated dependency graph contains the following SCCs: {p5, p7, p9} {p2, p4} {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: if_gcd#(false(),s(x),s(y)) -> gcd#(minus(y,x),s(x)) p2: gcd#(s(x),s(y)) -> if_gcd#(le(y,x),s(x),s(y)) p3: if_gcd#(true(),s(x),s(y)) -> gcd#(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: gcd(|0|(),y) -> y r9: gcd(s(x),|0|()) -> s(x) r10: gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) r11: if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) r12: if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: if_gcd#_A(x1,x2,x3) = max{37, x1 + 2, x2 - 21, x3 - 40} false_A = 2 s_A(x1) = max{49, x1 + 29} gcd#_A(x1,x2) = max{19, x1 - 12, x2 - 40} minus_A(x1,x2) = max{19, x1} le_A(x1,x2) = max{18, x2 - 48} true_A = 4 |0|_A = 49 if_minus_A(x1,x2,x3) = max{28, x2} base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: if_gcd#_A(x1,x2,x3) = x2 + x3 false_A() = 1 s_A(x1) = x1 + 4 gcd#_A(x1,x2) = x1 + x2 minus_A(x1,x2) = x1 + 1 le_A(x1,x2) = x1 + 1 true_A() = 1 |0|_A() = 3 if_minus_A(x1,x2,x3) = x2 + 1 if_gcd#!_A(x1,x2,x3) = x2 + 1 false!_A() = 6 s!_A(x1) = 8 gcd#!_A(x1,x2) = x1 + 3 minus!_A(x1,x2) = x1 + 5 le!_A(x1,x2) = x1 + x2 + 9 true!_A() = 3 |0|!_A() = 7 if_minus!_A(x1,x2,x3) = 8 partial status: pi(if_gcd#) = [1] pi(false) = [] pi(s) = [] pi(gcd#) = [] pi(minus) = [] pi(le) = [] pi(true) = [] pi(|0|) = [] pi(if_minus) = [] The following rules are removed: p1, p2, p3 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: gcd(|0|(),y) -> y r9: gcd(s(x),|0|()) -> s(x) r10: gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) r11: if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) r12: if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) The set of usable rules consists of r1, r2, r3, r4 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: if_minus#_A(x1,x2,x3) = max{12, x1 - 10, x2 + 1} false_A = 5 s_A(x1) = max{11, x1 + 4} minus#_A(x1,x2) = max{6, x1 + 1} le_A(x1,x2) = max{1, x1 - 2} |0|_A = 10 true_A = 7 minus_A(x1,x2) = max{17, x1 + 10, x2 - 1} base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: if_minus#_A(x1,x2,x3) = 0 false_A() = 1 s_A(x1) = 3 minus#_A(x1,x2) = 0 le_A(x1,x2) = 1 |0|_A() = 3 true_A() = 1 minus_A(x1,x2) = x1 + x2 + 5 if_minus#!_A(x1,x2,x3) = 5 false!_A() = 10 s!_A(x1) = x1 + 4 minus#!_A(x1,x2) = x1 + 3 le!_A(x1,x2) = 1 |0|!_A() = 3 true!_A() = 0 minus!_A(x1,x2) = 11 partial status: pi(if_minus#) = [] pi(false) = [] pi(s) = [1] pi(minus#) = [1] pi(le) = [] pi(|0|) = [] pi(true) = [] pi(minus) = [1] The following rules are removed: p1, p2 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: gcd(|0|(),y) -> y r9: gcd(s(x),|0|()) -> s(x) r10: gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) r11: if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) r12: if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) The set of usable rules consists of r4 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: le#_A(x1,x2) = max{12, x2 - 1} s_A(x1) = x1 + 16 minus_A(x1,x2) = max{10, x1 - 16} |0|_A = 9 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: le#_A(x1,x2) = x1 + x2 s_A(x1) = x1 + 2 minus_A(x1,x2) = x1 + x2 + 4 |0|_A() = 1 le#!_A(x1,x2) = 0 s!_A(x1) = x1 + 4 minus!_A(x1,x2) = 1 |0|!_A() = 8 partial status: pi(le#) = [] pi(s) = [1] pi(minus) = [] pi(|0|) = [] The following rules are removed: p1 Then no dependency pair remains.