Certification Problem

Input (TPDB TRS_Standard/Transformed_CSR_04/PALINDROME_complete-noand_L)

The rewrite relation of the following TRS is considered.

__(__(X,Y),Z) __(X,__(Y,Z)) (1)
__(X,nil) X (2)
__(nil,X) X (3)
U11(tt) U12(isPalListKind) (4)
U12(tt) U13(isNeList) (5)
U13(tt) tt (6)
U21(tt) U22(isPalListKind) (7)
U22(tt) U23(isPalListKind) (8)
U23(tt) U24(isPalListKind) (9)
U24(tt) U25(isList) (10)
U25(tt) U26(isList) (11)
U26(tt) tt (12)
U31(tt) U32(isPalListKind) (13)
U32(tt) U33(isQid) (14)
U33(tt) tt (15)
U41(tt) U42(isPalListKind) (16)
U42(tt) U43(isPalListKind) (17)
U43(tt) U44(isPalListKind) (18)
U44(tt) U45(isList) (19)
U45(tt) U46(isNeList) (20)
U46(tt) tt (21)
U51(tt) U52(isPalListKind) (22)
U52(tt) U53(isPalListKind) (23)
U53(tt) U54(isPalListKind) (24)
U54(tt) U55(isNeList) (25)
U55(tt) U56(isList) (26)
U56(tt) tt (27)
U61(tt) U62(isPalListKind) (28)
U62(tt) U63(isQid) (29)
U63(tt) tt (30)
U71(tt) U72(isPalListKind) (31)
U72(tt) U73(isPal) (32)
U73(tt) U74(isPalListKind) (33)
U74(tt) tt (34)
U81(tt) U82(isPalListKind) (35)
U82(tt) U83(isNePal) (36)
U83(tt) tt (37)
U91(tt) U92(isPalListKind) (38)
U92(tt) tt (39)
isList U11(isPalListKind) (40)
isList tt (41)
isList U21(isPalListKind) (42)
isNeList U31(isPalListKind) (43)
isNeList U41(isPalListKind) (44)
isNeList U51(isPalListKind) (45)
isNePal U61(isPalListKind) (46)
isNePal U71(isQid) (47)
isPal U81(isPalListKind) (48)
isPal tt (49)
isPalListKind tt (50)
isPalListKind U91(isPalListKind) (51)
isQid tt (52)

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

The following rules have been removed.
__(X,nil) X (2)
__(nil,X) X (3)

1.1 Rule Removal

The following rules have been removed.
__(__(X,Y),Z) __(X,__(Y,Z)) (1)

1.1.1 Rule Removal

The following rules have been removed.
U62(tt) U63(isQid) (29)
isPal tt (49)

1.1.1.1 Rule Removal

The following rules have been removed.
U63(tt) tt (30)

1.1.1.1.1 Rule Removal

The following rules have been removed.
U61(tt) U62(isPalListKind) (28)

1.1.1.1.1.1 Rule Removal

The following rules have been removed.
isNePal U61(isPalListKind) (46)

1.1.1.1.1.1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
U11#(tt) U12#(isPalListKind) (53)
U11#(tt) isPalListKind# (54)
U12#(tt) U13#(isNeList) (55)
U12#(tt) isNeList# (56)
U21#(tt) U22#(isPalListKind) (57)
U21#(tt) isPalListKind# (58)
U22#(tt) U23#(isPalListKind) (59)
U22#(tt) isPalListKind# (60)
U23#(tt) U24#(isPalListKind) (61)
U23#(tt) isPalListKind# (62)
U24#(tt) U25#(isList) (63)
U24#(tt) isList# (64)
U25#(tt) U26#(isList) (65)
U25#(tt) isList# (66)
U31#(tt) U32#(isPalListKind) (67)
U31#(tt) isPalListKind# (68)
U32#(tt) U33#(isQid) (69)
U32#(tt) isQid# (70)
U41#(tt) U42#(isPalListKind) (71)
U41#(tt) isPalListKind# (72)
U42#(tt) U43#(isPalListKind) (73)
U42#(tt) isPalListKind# (74)
U43#(tt) U44#(isPalListKind) (75)
U43#(tt) isPalListKind# (76)
U44#(tt) U45#(isList) (77)
U44#(tt) isList# (78)
U45#(tt) U46#(isNeList) (79)
U45#(tt) isNeList# (80)
U51#(tt) U52#(isPalListKind) (81)
U51#(tt) isPalListKind# (82)
U52#(tt) U53#(isPalListKind) (83)
U52#(tt) isPalListKind# (84)
U53#(tt) U54#(isPalListKind) (85)
U53#(tt) isPalListKind# (86)
U54#(tt) U55#(isNeList) (87)
U54#(tt) isNeList# (88)
U55#(tt) U56#(isList) (89)
U55#(tt) isList# (90)
U71#(tt) U72#(isPalListKind) (91)
U71#(tt) isPalListKind# (92)
U72#(tt) U73#(isPal) (93)
U72#(tt) isPal# (94)
U73#(tt) U74#(isPalListKind) (95)
U73#(tt) isPalListKind# (96)
U81#(tt) U82#(isPalListKind) (97)
U81#(tt) isPalListKind# (98)
U82#(tt) U83#(isNePal) (99)
U82#(tt) isNePal# (100)
U91#(tt) U92#(isPalListKind) (101)
U91#(tt) isPalListKind# (102)
isList# U11#(isPalListKind) (103)
isList# isPalListKind# (104)
isList# U21#(isPalListKind) (105)
isNeList# U31#(isPalListKind) (106)
isNeList# isPalListKind# (107)
isNeList# U41#(isPalListKind) (108)
isNeList# U51#(isPalListKind) (109)
isNePal# U71#(isQid) (110)
isNePal# isQid# (111)
isPal# U81#(isPalListKind) (112)
isPal# isPalListKind# (113)
isPalListKind# U91#(isPalListKind) (114)
isPalListKind# isPalListKind# (115)
It remains to prove infiniteness of the resulting DP problem.

1.1.1.1.1.1.1.1 Pair and Rule Removal

Some pairs and rules have been removed and it remains to prove infiniteness of the remaing problem. The following pairs have been deleted.
U11#(tt) U12#(isPalListKind) (53)
U11#(tt) isPalListKind# (54)
U12#(tt) U13#(isNeList) (55)
U12#(tt) isNeList# (56)
U21#(tt) U22#(isPalListKind) (57)
U21#(tt) isPalListKind# (58)
U22#(tt) U23#(isPalListKind) (59)
U22#(tt) isPalListKind# (60)
U23#(tt) U24#(isPalListKind) (61)
U23#(tt) isPalListKind# (62)
U24#(tt) U25#(isList) (63)
U24#(tt) isList# (64)
U25#(tt) U26#(isList) (65)
U25#(tt) isList# (66)
U31#(tt) U32#(isPalListKind) (67)
U31#(tt) isPalListKind# (68)
U32#(tt) U33#(isQid) (69)
U32#(tt) isQid# (70)
U41#(tt) U42#(isPalListKind) (71)
U41#(tt) isPalListKind# (72)
U42#(tt) U43#(isPalListKind) (73)
U42#(tt) isPalListKind# (74)
U43#(tt) U44#(isPalListKind) (75)
U43#(tt) isPalListKind# (76)
U44#(tt) U45#(isList) (77)
U44#(tt) isList# (78)
U45#(tt) U46#(isNeList) (79)
U45#(tt) isNeList# (80)
U51#(tt) U52#(isPalListKind) (81)
U51#(tt) isPalListKind# (82)
U52#(tt) U53#(isPalListKind) (83)
U52#(tt) isPalListKind# (84)
U53#(tt) U54#(isPalListKind) (85)
U53#(tt) isPalListKind# (86)
U54#(tt) U55#(isNeList) (87)
U54#(tt) isNeList# (88)
U55#(tt) U56#(isList) (89)
U55#(tt) isList# (90)
U71#(tt) U72#(isPalListKind) (91)
U71#(tt) isPalListKind# (92)
U72#(tt) U73#(isPal) (93)
U72#(tt) isPal# (94)
U73#(tt) U74#(isPalListKind) (95)
U73#(tt) isPalListKind# (96)
U81#(tt) U82#(isPalListKind) (97)
U81#(tt) isPalListKind# (98)
U82#(tt) U83#(isNePal) (99)
U82#(tt) isNePal# (100)
U91#(tt) U92#(isPalListKind) (101)
isList# U11#(isPalListKind) (103)
isList# isPalListKind# (104)
isList# U21#(isPalListKind) (105)
isNeList# U31#(isPalListKind) (106)
isNeList# isPalListKind# (107)
isNeList# U41#(isPalListKind) (108)
isNeList# U51#(isPalListKind) (109)
isNePal# U71#(isQid) (110)
isNePal# isQid# (111)
isPal# U81#(isPalListKind) (112)
isPal# isPalListKind# (113)
and the following rules have been deleted.

1.1.1.1.1.1.1.1.1 Pair and Rule Removal

Some pairs and rules have been removed and it remains to prove infiniteness of the remaing problem. The following pairs have been deleted. and the following rules have been deleted.
U11(tt) U12(isPalListKind) (4)
U12(tt) U13(isNeList) (5)
U13(tt) tt (6)
U21(tt) U22(isPalListKind) (7)
U22(tt) U23(isPalListKind) (8)
U23(tt) U24(isPalListKind) (9)
U24(tt) U25(isList) (10)
U25(tt) U26(isList) (11)
U26(tt) tt (12)
U31(tt) U32(isPalListKind) (13)
U32(tt) U33(isQid) (14)
U33(tt) tt (15)
U41(tt) U42(isPalListKind) (16)
U42(tt) U43(isPalListKind) (17)
U43(tt) U44(isPalListKind) (18)
U44(tt) U45(isList) (19)
U45(tt) U46(isNeList) (20)
U46(tt) tt (21)
U51(tt) U52(isPalListKind) (22)
U52(tt) U53(isPalListKind) (23)
U53(tt) U54(isPalListKind) (24)
U54(tt) U55(isNeList) (25)
U55(tt) U56(isList) (26)
U56(tt) tt (27)
U71(tt) U72(isPalListKind) (31)
U72(tt) U73(isPal) (32)
U73(tt) U74(isPalListKind) (33)
U74(tt) tt (34)
U81(tt) U82(isPalListKind) (35)
U82(tt) U83(isNePal) (36)
U83(tt) tt (37)
isList U11(isPalListKind) (40)
isList tt (41)
isList U21(isPalListKind) (42)
isNeList U31(isPalListKind) (43)
isNeList U41(isPalListKind) (44)
isNeList U51(isPalListKind) (45)
isNePal U71(isQid) (47)
isPal U81(isPalListKind) (48)
isQid tt (52)

1.1.1.1.1.1.1.1.1.1 Narrowing Processor

We consider narrowings of the pair below position 1 to get the following set of pairs
isPalListKind# U91#(tt) (116)
isPalListKind# U91#(U91(isPalListKind)) (117)

1.1.1.1.1.1.1.1.1.1.1 Loop

The following loop proves infiniteness of the DP problem.

t0 = isPalListKind#
P isPalListKind#
= t1
where t1 = t0