YES We show the termination of the TRS R: cond(true(),x) -> cond(odd(x),p(p(p(x)))) odd(|0|()) -> false() odd(s(|0|())) -> true() odd(s(s(x))) -> odd(x) p(|0|()) -> |0|() p(s(x)) -> x -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: cond#(true(),x) -> cond#(odd(x),p(p(p(x)))) p2: cond#(true(),x) -> odd#(x) p3: cond#(true(),x) -> p#(p(p(x))) p4: cond#(true(),x) -> p#(p(x)) p5: cond#(true(),x) -> p#(x) p6: odd#(s(s(x))) -> odd#(x) and R consists of: r1: cond(true(),x) -> cond(odd(x),p(p(p(x)))) r2: odd(|0|()) -> false() r3: odd(s(|0|())) -> true() r4: odd(s(s(x))) -> odd(x) r5: p(|0|()) -> |0|() r6: p(s(x)) -> x The estimated dependency graph contains the following SCCs: {p1} {p6} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: cond#(true(),x) -> cond#(odd(x),p(p(p(x)))) and R consists of: r1: cond(true(),x) -> cond(odd(x),p(p(p(x)))) r2: odd(|0|()) -> false() r3: odd(s(|0|())) -> true() r4: odd(s(s(x))) -> odd(x) r5: p(|0|()) -> |0|() r6: p(s(x)) -> x The set of usable rules consists of r2, r3, r4, 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!): max/plus interpretation on natural numbers: cond#_A(x1,x2) = max{0, x1 - 25, x2 - 2} true_A = 9 odd_A(x1) = max{3, x1 + 1} p_A(x1) = max{1, x1 - 7} |0|_A = 0 false_A = 3 s_A(x1) = max{18, x1 + 7} cond#!_A(x1,x2) = max{x1, x2 + 5} true!_A = 11 odd!_A(x1) = 10 p!_A(x1) = max{21, x1 + 19} |0|!_A = 20 false!_A = 1 s!_A(x1) = 12 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: cond#_A(x1,x2) = 0 true_A() = 2 odd_A(x1) = x1 + 1 p_A(x1) = x1 + 1 |0|_A() = 1 false_A() = 0 s_A(x1) = x1 + 1 cond#!_A(x1,x2) = x1 + 3 true!_A() = 2 odd!_A(x1) = 1 p!_A(x1) = 4 |0|!_A() = 3 false!_A() = 0 s!_A(x1) = 3 partial status: pi(cond#) = [] pi(true) = [] pi(odd) = [1] pi(p) = [1] pi(|0|) = [] pi(false) = [] 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: odd#(s(s(x))) -> odd#(x) and R consists of: r1: cond(true(),x) -> cond(odd(x),p(p(p(x)))) r2: odd(|0|()) -> false() r3: odd(s(|0|())) -> true() r4: odd(s(s(x))) -> odd(x) r5: p(|0|()) -> |0|() r6: p(s(x)) -> x 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!): max/plus interpretation on natural numbers: odd#_A(x1) = 0 s_A(x1) = max{0, x1 - 1} odd#!_A(x1) = 0 s!_A(x1) = max{0, x1 - 13} 2. marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: odd#_A(x1) = x1 s_A(x1) = x1 + 1 odd#!_A(x1) = 3 s!_A(x1) = 3 partial status: pi(odd#) = [1] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.