YES We show the termination of the TRS R: __(__(X,Y),Z) -> __(X,__(Y,Z)) __(X,nil()) -> X __(nil(),X) -> X and(tt(),X) -> activate(X) isList(V) -> isNeList(activate(V)) isList(n__nil()) -> tt() isList(n____(V1,V2)) -> and(isList(activate(V1)),n__isList(activate(V2))) isNeList(V) -> isQid(activate(V)) isNeList(n____(V1,V2)) -> and(isList(activate(V1)),n__isNeList(activate(V2))) isNeList(n____(V1,V2)) -> and(isNeList(activate(V1)),n__isList(activate(V2))) isNePal(V) -> isQid(activate(V)) isNePal(n____(I,__(P,I))) -> and(isQid(activate(I)),n__isPal(activate(P))) isPal(V) -> isNePal(activate(V)) isPal(n__nil()) -> tt() isQid(n__a()) -> tt() isQid(n__e()) -> tt() isQid(n__i()) -> tt() isQid(n__o()) -> tt() isQid(n__u()) -> tt() nil() -> n__nil() __(X1,X2) -> n____(X1,X2) isList(X) -> n__isList(X) isNeList(X) -> n__isNeList(X) isPal(X) -> n__isPal(X) a() -> n__a() e() -> n__e() i() -> n__i() o() -> n__o() u() -> n__u() activate(n__nil()) -> nil() activate(n____(X1,X2)) -> __(X1,X2) activate(n__isList(X)) -> isList(X) activate(n__isNeList(X)) -> isNeList(X) activate(n__isPal(X)) -> isPal(X) activate(n__a()) -> a() activate(n__e()) -> e() activate(n__i()) -> i() activate(n__o()) -> o() activate(n__u()) -> u() activate(X) -> X -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: __#(__(X,Y),Z) -> __#(X,__(Y,Z)) p2: __#(__(X,Y),Z) -> __#(Y,Z) p3: and#(tt(),X) -> activate#(X) p4: isList#(V) -> isNeList#(activate(V)) p5: isList#(V) -> activate#(V) p6: isList#(n____(V1,V2)) -> and#(isList(activate(V1)),n__isList(activate(V2))) p7: isList#(n____(V1,V2)) -> isList#(activate(V1)) p8: isList#(n____(V1,V2)) -> activate#(V1) p9: isList#(n____(V1,V2)) -> activate#(V2) p10: isNeList#(V) -> isQid#(activate(V)) p11: isNeList#(V) -> activate#(V) p12: isNeList#(n____(V1,V2)) -> and#(isList(activate(V1)),n__isNeList(activate(V2))) p13: isNeList#(n____(V1,V2)) -> isList#(activate(V1)) p14: isNeList#(n____(V1,V2)) -> activate#(V1) p15: isNeList#(n____(V1,V2)) -> activate#(V2) p16: isNeList#(n____(V1,V2)) -> and#(isNeList(activate(V1)),n__isList(activate(V2))) p17: isNeList#(n____(V1,V2)) -> isNeList#(activate(V1)) p18: isNeList#(n____(V1,V2)) -> activate#(V1) p19: isNeList#(n____(V1,V2)) -> activate#(V2) p20: isNePal#(V) -> isQid#(activate(V)) p21: isNePal#(V) -> activate#(V) p22: isNePal#(n____(I,__(P,I))) -> and#(isQid(activate(I)),n__isPal(activate(P))) p23: isNePal#(n____(I,__(P,I))) -> isQid#(activate(I)) p24: isNePal#(n____(I,__(P,I))) -> activate#(I) p25: isNePal#(n____(I,__(P,I))) -> activate#(P) p26: isPal#(V) -> isNePal#(activate(V)) p27: isPal#(V) -> activate#(V) p28: activate#(n__nil()) -> nil#() p29: activate#(n____(X1,X2)) -> __#(X1,X2) p30: activate#(n__isList(X)) -> isList#(X) p31: activate#(n__isNeList(X)) -> isNeList#(X) p32: activate#(n__isPal(X)) -> isPal#(X) p33: activate#(n__a()) -> a#() p34: activate#(n__e()) -> e#() p35: activate#(n__i()) -> i#() p36: activate#(n__o()) -> o#() p37: activate#(n__u()) -> u#() and R consists of: r1: __(__(X,Y),Z) -> __(X,__(Y,Z)) r2: __(X,nil()) -> X r3: __(nil(),X) -> X r4: and(tt(),X) -> activate(X) r5: isList(V) -> isNeList(activate(V)) r6: isList(n__nil()) -> tt() r7: isList(n____(V1,V2)) -> and(isList(activate(V1)),n__isList(activate(V2))) r8: isNeList(V) -> isQid(activate(V)) r9: isNeList(n____(V1,V2)) -> and(isList(activate(V1)),n__isNeList(activate(V2))) r10: isNeList(n____(V1,V2)) -> and(isNeList(activate(V1)),n__isList(activate(V2))) r11: isNePal(V) -> isQid(activate(V)) r12: isNePal(n____(I,__(P,I))) -> and(isQid(activate(I)),n__isPal(activate(P))) r13: isPal(V) -> isNePal(activate(V)) r14: isPal(n__nil()) -> tt() r15: isQid(n__a()) -> tt() r16: isQid(n__e()) -> tt() r17: isQid(n__i()) -> tt() r18: isQid(n__o()) -> tt() r19: isQid(n__u()) -> tt() r20: nil() -> n__nil() r21: __(X1,X2) -> n____(X1,X2) r22: isList(X) -> n__isList(X) r23: isNeList(X) -> n__isNeList(X) r24: isPal(X) -> n__isPal(X) r25: a() -> n__a() r26: e() -> n__e() r27: i() -> n__i() r28: o() -> n__o() r29: u() -> n__u() r30: activate(n__nil()) -> nil() r31: activate(n____(X1,X2)) -> __(X1,X2) r32: activate(n__isList(X)) -> isList(X) r33: activate(n__isNeList(X)) -> isNeList(X) r34: activate(n__isPal(X)) -> isPal(X) r35: activate(n__a()) -> a() r36: activate(n__e()) -> e() r37: activate(n__i()) -> i() r38: activate(n__o()) -> o() r39: activate(n__u()) -> u() r40: activate(X) -> X The estimated dependency graph contains the following SCCs: {p3, p4, p5, p6, p7, p8, p9, p11, p12, p13, p14, p15, p16, p17, p18, p19, p21, p22, p24, p25, p26, p27, p30, p31, p32} {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: isPal#(V) -> activate#(V) p2: activate#(n__isPal(X)) -> isPal#(X) p3: isPal#(V) -> isNePal#(activate(V)) p4: isNePal#(n____(I,__(P,I))) -> activate#(P) p5: activate#(n__isNeList(X)) -> isNeList#(X) p6: isNeList#(n____(V1,V2)) -> activate#(V2) p7: activate#(n__isList(X)) -> isList#(X) p8: isList#(n____(V1,V2)) -> activate#(V2) p9: isList#(n____(V1,V2)) -> activate#(V1) p10: isList#(n____(V1,V2)) -> isList#(activate(V1)) p11: isList#(n____(V1,V2)) -> and#(isList(activate(V1)),n__isList(activate(V2))) p12: and#(tt(),X) -> activate#(X) p13: isList#(V) -> activate#(V) p14: isList#(V) -> isNeList#(activate(V)) p15: isNeList#(n____(V1,V2)) -> activate#(V1) p16: isNeList#(n____(V1,V2)) -> isNeList#(activate(V1)) p17: isNeList#(n____(V1,V2)) -> and#(isNeList(activate(V1)),n__isList(activate(V2))) p18: isNeList#(n____(V1,V2)) -> isList#(activate(V1)) p19: isNeList#(n____(V1,V2)) -> and#(isList(activate(V1)),n__isNeList(activate(V2))) p20: isNeList#(V) -> activate#(V) p21: isNePal#(n____(I,__(P,I))) -> activate#(I) p22: isNePal#(n____(I,__(P,I))) -> and#(isQid(activate(I)),n__isPal(activate(P))) p23: isNePal#(V) -> activate#(V) and R consists of: r1: __(__(X,Y),Z) -> __(X,__(Y,Z)) r2: __(X,nil()) -> X r3: __(nil(),X) -> X r4: and(tt(),X) -> activate(X) r5: isList(V) -> isNeList(activate(V)) r6: isList(n__nil()) -> tt() r7: isList(n____(V1,V2)) -> and(isList(activate(V1)),n__isList(activate(V2))) r8: isNeList(V) -> isQid(activate(V)) r9: isNeList(n____(V1,V2)) -> and(isList(activate(V1)),n__isNeList(activate(V2))) r10: isNeList(n____(V1,V2)) -> and(isNeList(activate(V1)),n__isList(activate(V2))) r11: isNePal(V) -> isQid(activate(V)) r12: isNePal(n____(I,__(P,I))) -> and(isQid(activate(I)),n__isPal(activate(P))) r13: isPal(V) -> isNePal(activate(V)) r14: isPal(n__nil()) -> tt() r15: isQid(n__a()) -> tt() r16: isQid(n__e()) -> tt() r17: isQid(n__i()) -> tt() r18: isQid(n__o()) -> tt() r19: isQid(n__u()) -> tt() r20: nil() -> n__nil() r21: __(X1,X2) -> n____(X1,X2) r22: isList(X) -> n__isList(X) r23: isNeList(X) -> n__isNeList(X) r24: isPal(X) -> n__isPal(X) r25: a() -> n__a() r26: e() -> n__e() r27: i() -> n__i() r28: o() -> n__o() r29: u() -> n__u() r30: activate(n__nil()) -> nil() r31: activate(n____(X1,X2)) -> __(X1,X2) r32: activate(n__isList(X)) -> isList(X) r33: activate(n__isNeList(X)) -> isNeList(X) r34: activate(n__isPal(X)) -> isPal(X) r35: activate(n__a()) -> a() r36: activate(n__e()) -> e() r37: activate(n__i()) -> i() r38: activate(n__o()) -> o() r39: activate(n__u()) -> u() r40: activate(X) -> X The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16, r17, r18, r19, r20, r21, r22, r23, r24, r25, r26, r27, r28, r29, r30, r31, r32, r33, r34, r35, r36, r37, r38, r39, r40 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: isPal#_A(x1) = x1 + 10 activate#_A(x1) = max{3, x1} n__isPal_A(x1) = x1 + 11 isNePal#_A(x1) = x1 + 7 activate_A(x1) = max{2, x1} n_____A(x1,x2) = max{14, x1 + 12, x2} ___A(x1,x2) = max{14, x1 + 12, x2} n__isNeList_A(x1) = max{4, x1} isNeList#_A(x1) = max{3, x1} n__isList_A(x1) = max{5, x1} isList#_A(x1) = max{3, x1} and#_A(x1,x2) = max{x1 + 6, x2} isList_A(x1) = max{5, x1} tt_A = 9 isNeList_A(x1) = max{4, x1} isQid_A(x1) = max{0, x1 - 9} isNePal_A(x1) = max{8, x1 + 7} and_A(x1,x2) = max{x1 - 6, x2} nil_A = 10 isPal_A(x1) = x1 + 11 n__nil_A = 10 a_A = 19 n__a_A = 19 e_A = 19 n__e_A = 19 i_A = 19 n__i_A = 19 o_A = 19 n__o_A = 19 u_A = 19 n__u_A = 19 precedence: n____ = __ > isPal# > n__isPal = isNePal = isPal > n__isList = isList = and > isNePal# = and# > isList# > activate = isNeList = a = n__a > i > n__isNeList = n__i > isNeList# > activate# = isQid > u > nil = e = n__e = o = n__o = n__u > tt = n__nil partial status: pi(isPal#) = [1] pi(activate#) = [1] pi(n__isPal) = [1] pi(isNePal#) = [1] pi(activate) = [1] pi(n____) = [1, 2] pi(__) = [1, 2] pi(n__isNeList) = [1] pi(isNeList#) = [1] pi(n__isList) = [1] pi(isList#) = [1] pi(and#) = [2] pi(isList) = [1] pi(tt) = [] pi(isNeList) = [1] pi(isQid) = [] pi(isNePal) = [] pi(and) = [2] pi(nil) = [] pi(isPal) = [1] pi(n__nil) = [] pi(a) = [] pi(n__a) = [] pi(e) = [] pi(n__e) = [] pi(i) = [] pi(n__i) = [] pi(o) = [] pi(n__o) = [] pi(u) = [] pi(n__u) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: isPal#_A(x1) = x1 + 574 activate#_A(x1) = x1 n__isPal_A(x1) = x1 + 575 isNePal#_A(x1) = 312 activate_A(x1) = 36 n_____A(x1,x2) = max{x1 + 210, x2 + 6} ___A(x1,x2) = max{x1 + 211, x2 + 608} n__isNeList_A(x1) = max{207, x1 + 46} isNeList#_A(x1) = x1 + 45 n__isList_A(x1) = x1 + 102 isList#_A(x1) = x1 + 101 and#_A(x1,x2) = 43 isList_A(x1) = x1 + 329 tt_A = 316 isNeList_A(x1) = max{207, x1 + 47} isQid_A(x1) = 317 isNePal_A(x1) = 316 and_A(x1,x2) = 36 nil_A = 35 isPal_A(x1) = x1 + 575 n__nil_A = 0 a_A = 35 n__a_A = 0 e_A = 1 n__e_A = 0 i_A = 35 n__i_A = 0 o_A = 35 n__o_A = 0 u_A = 35 n__u_A = 0 precedence: nil = n__a = e > isPal = n__e > tt = isQid > isNePal = o > isList = n__nil > activate = isNeList = and > n____ = __ = n__i > n__u > n__isNeList = n__o > i > isNePal# = isNeList# = and# > isList# > n__isList > n__isPal > isPal# > a > u > activate# partial status: pi(isPal#) = [1] pi(activate#) = [1] pi(n__isPal) = [] pi(isNePal#) = [] pi(activate) = [] pi(n____) = [] pi(__) = [2] pi(n__isNeList) = [1] pi(isNeList#) = [1] pi(n__isList) = [1] pi(isList#) = [1] pi(and#) = [] pi(isList) = [] pi(tt) = [] pi(isNeList) = [1] pi(isQid) = [] pi(isNePal) = [] pi(and) = [] pi(nil) = [] pi(isPal) = [] pi(n__nil) = [] pi(a) = [] pi(n__a) = [] pi(e) = [] pi(n__e) = [] pi(i) = [] pi(n__i) = [] pi(o) = [] pi(n__o) = [] pi(u) = [] pi(n__u) = [] The next rules are strictly ordered: p1, p2, p3, p4, p5, p6, p7, p9, p10, p11, p12, p13, p14, p15, p16, p17, p18, p19, p20, p21, p22, p23 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: isList#(n____(V1,V2)) -> activate#(V2) and R consists of: r1: __(__(X,Y),Z) -> __(X,__(Y,Z)) r2: __(X,nil()) -> X r3: __(nil(),X) -> X r4: and(tt(),X) -> activate(X) r5: isList(V) -> isNeList(activate(V)) r6: isList(n__nil()) -> tt() r7: isList(n____(V1,V2)) -> and(isList(activate(V1)),n__isList(activate(V2))) r8: isNeList(V) -> isQid(activate(V)) r9: isNeList(n____(V1,V2)) -> and(isList(activate(V1)),n__isNeList(activate(V2))) r10: isNeList(n____(V1,V2)) -> and(isNeList(activate(V1)),n__isList(activate(V2))) r11: isNePal(V) -> isQid(activate(V)) r12: isNePal(n____(I,__(P,I))) -> and(isQid(activate(I)),n__isPal(activate(P))) r13: isPal(V) -> isNePal(activate(V)) r14: isPal(n__nil()) -> tt() r15: isQid(n__a()) -> tt() r16: isQid(n__e()) -> tt() r17: isQid(n__i()) -> tt() r18: isQid(n__o()) -> tt() r19: isQid(n__u()) -> tt() r20: nil() -> n__nil() r21: __(X1,X2) -> n____(X1,X2) r22: isList(X) -> n__isList(X) r23: isNeList(X) -> n__isNeList(X) r24: isPal(X) -> n__isPal(X) r25: a() -> n__a() r26: e() -> n__e() r27: i() -> n__i() r28: o() -> n__o() r29: u() -> n__u() r30: activate(n__nil()) -> nil() r31: activate(n____(X1,X2)) -> __(X1,X2) r32: activate(n__isList(X)) -> isList(X) r33: activate(n__isNeList(X)) -> isNeList(X) r34: activate(n__isPal(X)) -> isPal(X) r35: activate(n__a()) -> a() r36: activate(n__e()) -> e() r37: activate(n__i()) -> i() r38: activate(n__o()) -> o() r39: activate(n__u()) -> u() r40: activate(X) -> X The estimated dependency graph contains the following SCCs: (no SCCs) -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: __#(__(X,Y),Z) -> __#(X,__(Y,Z)) p2: __#(__(X,Y),Z) -> __#(Y,Z) and R consists of: r1: __(__(X,Y),Z) -> __(X,__(Y,Z)) r2: __(X,nil()) -> X r3: __(nil(),X) -> X r4: and(tt(),X) -> activate(X) r5: isList(V) -> isNeList(activate(V)) r6: isList(n__nil()) -> tt() r7: isList(n____(V1,V2)) -> and(isList(activate(V1)),n__isList(activate(V2))) r8: isNeList(V) -> isQid(activate(V)) r9: isNeList(n____(V1,V2)) -> and(isList(activate(V1)),n__isNeList(activate(V2))) r10: isNeList(n____(V1,V2)) -> and(isNeList(activate(V1)),n__isList(activate(V2))) r11: isNePal(V) -> isQid(activate(V)) r12: isNePal(n____(I,__(P,I))) -> and(isQid(activate(I)),n__isPal(activate(P))) r13: isPal(V) -> isNePal(activate(V)) r14: isPal(n__nil()) -> tt() r15: isQid(n__a()) -> tt() r16: isQid(n__e()) -> tt() r17: isQid(n__i()) -> tt() r18: isQid(n__o()) -> tt() r19: isQid(n__u()) -> tt() r20: nil() -> n__nil() r21: __(X1,X2) -> n____(X1,X2) r22: isList(X) -> n__isList(X) r23: isNeList(X) -> n__isNeList(X) r24: isPal(X) -> n__isPal(X) r25: a() -> n__a() r26: e() -> n__e() r27: i() -> n__i() r28: o() -> n__o() r29: u() -> n__u() r30: activate(n__nil()) -> nil() r31: activate(n____(X1,X2)) -> __(X1,X2) r32: activate(n__isList(X)) -> isList(X) r33: activate(n__isNeList(X)) -> isNeList(X) r34: activate(n__isPal(X)) -> isPal(X) r35: activate(n__a()) -> a() r36: activate(n__e()) -> e() r37: activate(n__i()) -> i() r38: activate(n__o()) -> o() r39: activate(n__u()) -> u() r40: activate(X) -> X The set of usable rules consists of r1, r2, r3, r21 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: __#_A(x1,x2) = max{x1 + 4, x2 + 2} ___A(x1,x2) = max{x1 + 2, x2} nil_A = 0 n_____A(x1,x2) = max{x1 + 2, x2} precedence: __# = __ > nil = n____ partial status: pi(__#) = [1] pi(__) = [1, 2] pi(nil) = [] pi(n____) = [1, 2] 2. weighted path order base order: max/plus interpretations on natural numbers: __#_A(x1,x2) = max{0, x1 - 3} ___A(x1,x2) = max{x1 + 5, x2 + 7} nil_A = 0 n_____A(x1,x2) = max{x1 + 6, x2 + 8} precedence: __# = __ = nil = n____ partial status: pi(__#) = [] pi(__) = [2] pi(nil) = [] pi(n____) = [] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.