YES We show the termination of the TRS R: cond(true(),x,y) -> cond(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) and(true(),true()) -> true() and(x,false()) -> false() and(false(),x) -> false() gr(|0|(),|0|()) -> false() gr(|0|(),x) -> false() gr(s(x),|0|()) -> true() gr(s(x),s(y)) -> gr(x,y) p(|0|()) -> |0|() p(s(x)) -> x -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: cond#(true(),x,y) -> cond#(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) p2: cond#(true(),x,y) -> and#(gr(x,|0|()),gr(y,|0|())) p3: cond#(true(),x,y) -> gr#(x,|0|()) p4: cond#(true(),x,y) -> gr#(y,|0|()) p5: cond#(true(),x,y) -> p#(x) p6: cond#(true(),x,y) -> p#(y) p7: gr#(s(x),s(y)) -> gr#(x,y) and R consists of: r1: cond(true(),x,y) -> cond(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) r2: and(true(),true()) -> true() r3: and(x,false()) -> false() r4: and(false(),x) -> false() r5: gr(|0|(),|0|()) -> false() r6: gr(|0|(),x) -> false() r7: gr(s(x),|0|()) -> true() r8: gr(s(x),s(y)) -> gr(x,y) r9: p(|0|()) -> |0|() r10: p(s(x)) -> x The estimated dependency graph contains the following SCCs: {p1} {p7} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: cond#(true(),x,y) -> cond#(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) and R consists of: r1: cond(true(),x,y) -> cond(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) r2: and(true(),true()) -> true() r3: and(x,false()) -> false() r4: and(false(),x) -> false() r5: gr(|0|(),|0|()) -> false() r6: gr(|0|(),x) -> false() r7: gr(s(x),|0|()) -> true() r8: gr(s(x),s(y)) -> gr(x,y) r9: p(|0|()) -> |0|() r10: p(s(x)) -> x The set of usable rules consists of r2, r3, r4, r5, r6, r7, r8, r9, r10 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: cond#_A(x1,x2,x3) = max{x1 - 31, x2 + 20} true_A = 63 and_A(x1,x2) = max{19, x1 + 14} gr_A(x1,x2) = max{16, x1 + 7} |0|_A = 9 p_A(x1) = max{11, x1 - 8} false_A = 15 s_A(x1) = max{64, x1 + 57} 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,x3) = 0 true_A() = 1 and_A(x1,x2) = x1 + x2 gr_A(x1,x2) = x1 + 1 |0|_A() = 1 p_A(x1) = x1 + 1 false_A() = 2 s_A(x1) = x1 cond#!_A(x1,x2,x3) = x1 + 3 true!_A() = 3 and!_A(x1,x2) = x1 + x2 gr!_A(x1,x2) = 1 |0|!_A() = 0 p!_A(x1) = 4 false!_A() = 1 s!_A(x1) = 4 partial status: pi(cond#) = [2] pi(true) = [] pi(and) = [] pi(gr) = [1] pi(|0|) = [] pi(p) = [] 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: gr#(s(x),s(y)) -> gr#(x,y) and R consists of: r1: cond(true(),x,y) -> cond(and(gr(x,|0|()),gr(y,|0|())),p(x),p(y)) r2: and(true(),true()) -> true() r3: and(x,false()) -> false() r4: and(false(),x) -> false() r5: gr(|0|(),|0|()) -> false() r6: gr(|0|(),x) -> false() r7: gr(s(x),|0|()) -> true() r8: gr(s(x),s(y)) -> gr(x,y) r9: p(|0|()) -> |0|() r10: 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: max/plus interpretation on natural numbers: gr#_A(x1,x2) = max{18, x2} s_A(x1) = x1 + 18 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: gr#_A(x1,x2) = x1 + x2 s_A(x1) = x1 + 1 gr#!_A(x1,x2) = 6 s!_A(x1) = 7 partial status: pi(gr#) = [2] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.