YES We show the termination of the TRS R: minus(x,|0|()) -> x minus(s(x),s(y)) -> minus(x,y) quot(|0|(),s(y)) -> |0|() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) plus(|0|(),y) -> y plus(s(x),y) -> s(plus(x,y)) minus(minus(x,y),z) -> minus(x,plus(y,z)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) p2: quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) p3: quot#(s(x),s(y)) -> minus#(x,y) p4: plus#(s(x),y) -> plus#(x,y) p5: minus#(minus(x,y),z) -> minus#(x,plus(y,z)) p6: minus#(minus(x,y),z) -> plus#(y,z) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) The estimated dependency graph contains the following SCCs: {p2} {p1, p5} {p4} -- 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: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) The set of usable rules consists of r1, r2, r5, r6, r7 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: quot#_A(x1,x2) = x1 s_A(x1) = x1 + 3 minus_A(x1,x2) = x1 + 1 |0|_A() = 2 plus_A(x1,x2) = x1 + x2 + 1 quot#!_A(x1,x2) = x1 + 1 s!_A(x1) = x1 + 3 minus!_A(x1,x2) = x1 + 5 |0|!_A() = 0 plus!_A(x1,x2) = x1 + x2 + 4 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: quot#_A(x1,x2) = max{0, x1 - 7, x2 - 6} s_A(x1) = max{4, x1} minus_A(x1,x2) = max{6, x1, x2 - 8} |0|_A = 4 plus_A(x1,x2) = max{6, x1 - 5, x2} quot#!_A(x1,x2) = 0 s!_A(x1) = max{12, x1 - 8} minus!_A(x1,x2) = max{14, x1 - 7, x2 - 22} |0|!_A = 3 plus!_A(x1,x2) = max{13, x1 - 7, x2 - 3} partial status: pi(quot#) = [] pi(s) = [1] pi(minus) = [1] pi(|0|) = [] pi(plus) = [1, 2] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) p2: minus#(minus(x,y),z) -> minus#(x,plus(y,z)) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) The set of usable rules consists of r1, r5, r6 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: minus#_A(x1,x2) = 0 s_A(x1) = 1 minus_A(x1,x2) = x1 + x2 + 2 plus_A(x1,x2) = x1 + x2 + 3 |0|_A() = 1 minus#!_A(x1,x2) = 1 s!_A(x1) = 2 minus!_A(x1,x2) = 0 plus!_A(x1,x2) = 3 |0|!_A() = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: minus#_A(x1,x2) = max{0, x1 - 10, x2 - 10} s_A(x1) = max{2, x1} minus_A(x1,x2) = max{x1 + 8, x2 - 10} plus_A(x1,x2) = max{9, x1 - 10, x2} |0|_A = 11 minus#!_A(x1,x2) = max{3, x1 - 3, x2 - 23} s!_A(x1) = max{1, x1 - 10} minus!_A(x1,x2) = max{2, x1 - 13, x2 - 34} plus!_A(x1,x2) = max{4, x1 - 9, x2 - 24} |0|!_A = 0 partial status: pi(minus#) = [1] pi(s) = [1] pi(minus) = [1] pi(plus) = [1, 2] pi(|0|) = [] 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: plus#(s(x),y) -> plus#(x,y) and R consists of: r1: minus(x,|0|()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: quot(|0|(),s(y)) -> |0|() r4: quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) r5: plus(|0|(),y) -> y r6: plus(s(x),y) -> s(plus(x,y)) r7: minus(minus(x,y),z) -> minus(x,plus(y,z)) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: lexicographic combination of reduction triples: 1. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: plus#_A(x1,x2) = x1 s_A(x1) = x1 + 1 plus#!_A(x1,x2) = 0 s!_A(x1) = 2 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: plus#_A(x1,x2) = 0 s_A(x1) = max{17, x1 - 5} plus#!_A(x1,x2) = x2 + 9 s!_A(x1) = max{7, x1 + 3} partial status: pi(plus#) = [1] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.