YES We show the termination of the TRS R: plus(|0|(),x) -> x plus(s(x),y) -> s(plus(p(s(x)),y)) times(|0|(),y) -> |0|() times(s(x),y) -> plus(y,times(p(s(x)),y)) exp(x,|0|()) -> s(|0|()) exp(x,s(y)) -> times(x,exp(x,y)) p(s(|0|())) -> |0|() p(s(s(x))) -> s(p(s(x))) tower(x,y) -> towerIter(x,y,s(|0|())) towerIter(|0|(),y,z) -> z towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(y,z)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(x),y) -> plus#(p(s(x)),y) p2: plus#(s(x),y) -> p#(s(x)) p3: times#(s(x),y) -> plus#(y,times(p(s(x)),y)) p4: times#(s(x),y) -> times#(p(s(x)),y) p5: times#(s(x),y) -> p#(s(x)) p6: exp#(x,s(y)) -> times#(x,exp(x,y)) p7: exp#(x,s(y)) -> exp#(x,y) p8: p#(s(s(x))) -> p#(s(x)) p9: tower#(x,y) -> towerIter#(x,y,s(|0|())) p10: towerIter#(s(x),y,z) -> towerIter#(p(s(x)),y,exp(y,z)) p11: towerIter#(s(x),y,z) -> p#(s(x)) p12: towerIter#(s(x),y,z) -> exp#(y,z) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(y,z)) The estimated dependency graph contains the following SCCs: {p10} {p7} {p4} {p1} {p8} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: towerIter#(s(x),y,z) -> towerIter#(p(s(x)),y,exp(y,z)) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(y,z)) The set of usable rules consists of r1, r7, r8 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: towerIter#_A(x1,x2,x3) = 0 s_A(x1) = 2 p_A(x1) = 6 exp_A(x1,x2) = x1 + 1 plus_A(x1,x2) = x2 + 1 |0|_A() = 6 towerIter#!_A(x1,x2,x3) = 2 s!_A(x1) = 6 p!_A(x1) = 6 exp!_A(x1,x2) = x1 + x2 + 1 plus!_A(x1,x2) = 0 |0|!_A() = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: towerIter#_A(x1,x2,x3) = max{0, x1 - 47, x2 - 28} s_A(x1) = x1 + 46 p_A(x1) = max{32, x1 - 14} exp_A(x1,x2) = max{33, x1 + 5, x2 + 1} plus_A(x1,x2) = max{105, x2 + 15} |0|_A = 104 towerIter#!_A(x1,x2,x3) = x2 + 2 s!_A(x1) = max{67, x1 + 34} p!_A(x1) = max{67, x1 - 24} exp!_A(x1,x2) = 0 plus!_A(x1,x2) = x2 + 50 |0|!_A = 68 partial status: pi(towerIter#) = [1] pi(s) = [1] pi(p) = [] pi(exp) = [] pi(plus) = [2] pi(|0|) = [] 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: exp#(x,s(y)) -> exp#(x,y) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(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: exp#_A(x1,x2) = x2 s_A(x1) = x1 + 3 exp#!_A(x1,x2) = 0 s!_A(x1) = 9 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: exp#_A(x1,x2) = 0 s_A(x1) = max{2, x1 - 7} exp#!_A(x1,x2) = max{0, x2 - 4} s!_A(x1) = max{22, x1 - 3} partial status: pi(exp#) = [2] pi(s) = [1] 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: times#(s(x),y) -> times#(p(s(x)),y) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(y,z)) The set of usable rules consists of r7, r8 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: times#_A(x1,x2) = x1 s_A(x1) = x1 + 3 p_A(x1) = x1 |0|_A() = 6 times#!_A(x1,x2) = 0 s!_A(x1) = 5 p!_A(x1) = x1 |0|!_A() = 6 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: times#_A(x1,x2) = max{0, x1 - 22, x2 - 24} s_A(x1) = x1 + 21 p_A(x1) = max{4, x1 - 17} |0|_A = 21 times#!_A(x1,x2) = max{8, x1 + 3} s!_A(x1) = x1 + 9 p!_A(x1) = 60 |0|!_A = 31 partial status: pi(times#) = [] pi(s) = [] pi(p) = [1] pi(|0|) = [] 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: plus#(s(x),y) -> plus#(p(s(x)),y) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(y,z)) The set of usable rules consists of r7, r8 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) = 0 s_A(x1) = x1 + 2 p_A(x1) = x1 |0|_A() = 5 plus#!_A(x1,x2) = x1 + 8 s!_A(x1) = x1 + 2 p!_A(x1) = 10 |0|!_A() = 0 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: plus#_A(x1,x2) = max{0, x1 - 21, x2 - 2} s_A(x1) = max{35, x1 + 22} p_A(x1) = max{20, x1 - 10} |0|_A = 64 plus#!_A(x1,x2) = max{25, x1 + 6} s!_A(x1) = max{24, x1 - 36} p!_A(x1) = max{23, x1 - 11} |0|!_A = 26 partial status: pi(plus#) = [1] pi(s) = [] pi(p) = [1] pi(|0|) = [] 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: p#(s(s(x))) -> p#(s(x)) and R consists of: r1: plus(|0|(),x) -> x r2: plus(s(x),y) -> s(plus(p(s(x)),y)) r3: times(|0|(),y) -> |0|() r4: times(s(x),y) -> plus(y,times(p(s(x)),y)) r5: exp(x,|0|()) -> s(|0|()) r6: exp(x,s(y)) -> times(x,exp(x,y)) r7: p(s(|0|())) -> |0|() r8: p(s(s(x))) -> s(p(s(x))) r9: tower(x,y) -> towerIter(x,y,s(|0|())) r10: towerIter(|0|(),y,z) -> z r11: towerIter(s(x),y,z) -> towerIter(p(s(x)),y,exp(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: p#_A(x1) = x1 s_A(x1) = x1 + 3 p#!_A(x1) = x1 + 2 s!_A(x1) = x1 + 4 2. marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: p#_A(x1) = 0 s_A(x1) = max{22, x1 - 21} p#!_A(x1) = 0 s!_A(x1) = max{10, x1 + 1} partial status: pi(p#) = [1] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.