YES We show the termination of the TRS R: cond(true(),x) -> cond(odd(x),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(x)) p2: cond#(true(),x) -> odd#(x) p3: cond#(true(),x) -> p#(x) p4: odd#(s(s(x))) -> odd#(x) and R consists of: r1: cond(true(),x) -> cond(odd(x),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} {p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: cond#(true(),x) -> cond#(odd(x),p(x)) and R consists of: r1: cond(true(),x) -> cond(odd(x),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: max/plus interpretation on natural numbers: cond#_A(x1,x2) = max{8, x1 - 2, x2 + 3} true_A = 12 odd_A(x1) = max{11, x1 + 2} p_A(x1) = max{4, x1 - 2} |0|_A = 3 false_A = 2 s_A(x1) = max{11, x1 + 3} base order 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() = 1 odd_A(x1) = 1 p_A(x1) = x1 + 1 |0|_A() = 1 false_A() = 0 s_A(x1) = x1 + 1 cond#!_A(x1,x2) = 2 true!_A() = 3 odd!_A(x1) = 1 p!_A(x1) = 1 |0|!_A() = 2 false!_A() = 0 s!_A(x1) = 2 partial status: pi(cond#) = [] pi(true) = [] pi(odd) = [1] pi(p) = [] 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(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 r5 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: odd#_A(x1) = 0 s_A(x1) = max{3, x1 - 4} p_A(x1) = max{7, x1 - 9} |0|_A = 2 base order 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 p_A(x1) = x1 + 4 |0|_A() = 1 odd#!_A(x1) = x1 + 4 s!_A(x1) = 3 p!_A(x1) = 3 |0|!_A() = 1 partial status: pi(odd#) = [] pi(s) = [] pi(p) = [] pi(|0|) = [] The following rules are removed: p1 Then no dependency pair remains.