Certification Problem

Input (TPDB SRS_Standard/Secret_06_SRS/secr10)

The rewrite relation of the following TRS is considered.

a(a(x1)) → c(b(a(b(a(x1))))) (1)
b(a(b(x1))) → b(x1) (2)
a(a(a(x1))) → c(c(a(x1))) (3)
c(c(x1)) → a(b(c(b(a(x1))))) (4)
a(c(a(x1))) → c(c(a(x1))) (5)
c(a(c(x1))) → a(a(c(x1))) (6)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Split

We split R in the relative problem D/R-D and R-D, where the rules D

a(a(x1)) → c(b(a(b(a(x1))))) (1)
b(a(b(x1))) → b(x1) (2)
c(c(x1)) → a(b(c(b(a(x1))))) (4)
are deleted.

1.1 Closure Under Flat Contexts

Using the flat contexts

{c(☐), b(☐), a(☐)}

We obtain the transformed TRS
c(a(a(x1))) → c(c(b(a(b(a(x1)))))) (7)
c(b(a(b(x1)))) → c(b(x1)) (8)
c(c(c(x1))) → c(a(b(c(b(a(x1)))))) (9)
b(a(a(x1))) → b(c(b(a(b(a(x1)))))) (10)
b(b(a(b(x1)))) → b(b(x1)) (11)
b(c(c(x1))) → b(a(b(c(b(a(x1)))))) (12)
a(a(a(x1))) → a(c(b(a(b(a(x1)))))) (13)
a(b(a(b(x1)))) → a(b(x1)) (14)
a(c(c(x1))) → a(a(b(c(b(a(x1)))))) (15)
c(a(a(a(x1)))) → c(c(c(a(x1)))) (16)
c(a(c(a(x1)))) → c(c(c(a(x1)))) (17)
c(c(a(c(x1)))) → c(a(a(c(x1)))) (18)
b(a(a(a(x1)))) → b(c(c(a(x1)))) (19)
b(a(c(a(x1)))) → b(c(c(a(x1)))) (20)
b(c(a(c(x1)))) → b(a(a(c(x1)))) (21)
a(a(a(a(x1)))) → a(c(c(a(x1)))) (22)
a(a(c(a(x1)))) → a(c(c(a(x1)))) (23)
a(c(a(c(x1)))) → a(a(a(c(x1)))) (24)

1.1.1 Semantic Labeling

The following interpretations form a model of the rules.

As carrier we take the set {0,1,2}. Symbols are labeled by the interpretation of their arguments using the interpretations (modulo 3):

[c(x1)] = 3x1 + 0
[b(x1)] = 3x1 + 1
[a(x1)] = 3x1 + 2

We obtain the labeled TRS
a2(a2(a2(x1))) → a0(c1(b2(a1(b2(a2(x1)))))) (25)
a2(a2(a0(x1))) → a0(c1(b2(a1(b2(a0(x1)))))) (26)
a2(a2(a1(x1))) → a0(c1(b2(a1(b2(a1(x1)))))) (27)
c2(a2(a2(x1))) → c0(c1(b2(a1(b2(a2(x1)))))) (28)
c2(a2(a0(x1))) → c0(c1(b2(a1(b2(a0(x1)))))) (29)
c2(a2(a1(x1))) → c0(c1(b2(a1(b2(a1(x1)))))) (30)
b2(a2(a2(x1))) → b0(c1(b2(a1(b2(a2(x1)))))) (31)
b2(a2(a0(x1))) → b0(c1(b2(a1(b2(a0(x1)))))) (32)
b2(a2(a1(x1))) → b0(c1(b2(a1(b2(a1(x1)))))) (33)
a1(b2(a1(b2(x1)))) → a1(b2(x1)) (34)
a1(b2(a1(b0(x1)))) → a1(b0(x1)) (35)
a1(b2(a1(b1(x1)))) → a1(b1(x1)) (36)
c1(b2(a1(b2(x1)))) → c1(b2(x1)) (37)
c1(b2(a1(b0(x1)))) → c1(b0(x1)) (38)
c1(b2(a1(b1(x1)))) → c1(b1(x1)) (39)
b1(b2(a1(b2(x1)))) → b1(b2(x1)) (40)
b1(b2(a1(b0(x1)))) → b1(b0(x1)) (41)
b1(b2(a1(b1(x1)))) → b1(b1(x1)) (42)
a0(c0(c2(x1))) → a2(a1(b0(c1(b2(a2(x1)))))) (43)
a0(c0(c0(x1))) → a2(a1(b0(c1(b2(a0(x1)))))) (44)
a0(c0(c1(x1))) → a2(a1(b0(c1(b2(a1(x1)))))) (45)
c0(c0(c2(x1))) → c2(a1(b0(c1(b2(a2(x1)))))) (46)
c0(c0(c0(x1))) → c2(a1(b0(c1(b2(a0(x1)))))) (47)
c0(c0(c1(x1))) → c2(a1(b0(c1(b2(a1(x1)))))) (48)
b0(c0(c2(x1))) → b2(a1(b0(c1(b2(a2(x1)))))) (49)
b0(c0(c0(x1))) → b2(a1(b0(c1(b2(a0(x1)))))) (50)
b0(c0(c1(x1))) → b2(a1(b0(c1(b2(a1(x1)))))) (51)
a2(a2(a2(a2(x1)))) → a0(c0(c2(a2(x1)))) (52)
a2(a2(a2(a0(x1)))) → a0(c0(c2(a0(x1)))) (53)
a2(a2(a2(a1(x1)))) → a0(c0(c2(a1(x1)))) (54)
c2(a2(a2(a2(x1)))) → c0(c0(c2(a2(x1)))) (55)
c2(a2(a2(a0(x1)))) → c0(c0(c2(a0(x1)))) (56)
c2(a2(a2(a1(x1)))) → c0(c0(c2(a1(x1)))) (57)
b2(a2(a2(a2(x1)))) → b0(c0(c2(a2(x1)))) (58)
b2(a2(a2(a0(x1)))) → b0(c0(c2(a0(x1)))) (59)
b2(a2(a2(a1(x1)))) → b0(c0(c2(a1(x1)))) (60)
a2(a0(c2(a2(x1)))) → a0(c0(c2(a2(x1)))) (61)
a2(a0(c2(a0(x1)))) → a0(c0(c2(a0(x1)))) (62)
a2(a0(c2(a1(x1)))) → a0(c0(c2(a1(x1)))) (63)
c2(a0(c2(a2(x1)))) → c0(c0(c2(a2(x1)))) (64)
c2(a0(c2(a0(x1)))) → c0(c0(c2(a0(x1)))) (65)
c2(a0(c2(a1(x1)))) → c0(c0(c2(a1(x1)))) (66)
b2(a0(c2(a2(x1)))) → b0(c0(c2(a2(x1)))) (67)
b2(a0(c2(a0(x1)))) → b0(c0(c2(a0(x1)))) (68)
b2(a0(c2(a1(x1)))) → b0(c0(c2(a1(x1)))) (69)
a0(c2(a0(c2(x1)))) → a2(a2(a0(c2(x1)))) (70)
a0(c2(a0(c0(x1)))) → a2(a2(a0(c0(x1)))) (71)
a0(c2(a0(c1(x1)))) → a2(a2(a0(c1(x1)))) (72)
c0(c2(a0(c2(x1)))) → c2(a2(a0(c2(x1)))) (73)
c0(c2(a0(c0(x1)))) → c2(a2(a0(c0(x1)))) (74)
c0(c2(a0(c1(x1)))) → c2(a2(a0(c1(x1)))) (75)
b0(c2(a0(c2(x1)))) → b2(a2(a0(c2(x1)))) (76)
b0(c2(a0(c0(x1)))) → b2(a2(a0(c0(x1)))) (77)
b0(c2(a0(c1(x1)))) → b2(a2(a0(c1(x1)))) (78)

1.1.1.1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c0(x1)] = x1 +
3
[c1(x1)] = x1 +
0
[c2(x1)] = x1 +
3
[b0(x1)] = x1 +
0
[b1(x1)] = x1 +
0
[b2(x1)] = x1 +
0
[a0(x1)] = x1 +
3
[a1(x1)] = x1 +
1
[a2(x1)] = x1 +
3
all of the following rules can be deleted.
a2(a2(a2(x1))) → a0(c1(b2(a1(b2(a2(x1)))))) (25)
a2(a2(a0(x1))) → a0(c1(b2(a1(b2(a0(x1)))))) (26)
a2(a2(a1(x1))) → a0(c1(b2(a1(b2(a1(x1)))))) (27)
c2(a2(a2(x1))) → c0(c1(b2(a1(b2(a2(x1)))))) (28)
c2(a2(a0(x1))) → c0(c1(b2(a1(b2(a0(x1)))))) (29)
c2(a2(a1(x1))) → c0(c1(b2(a1(b2(a1(x1)))))) (30)
b2(a2(a2(x1))) → b0(c1(b2(a1(b2(a2(x1)))))) (31)
b2(a2(a0(x1))) → b0(c1(b2(a1(b2(a0(x1)))))) (32)
b2(a2(a1(x1))) → b0(c1(b2(a1(b2(a1(x1)))))) (33)
a1(b2(a1(b2(x1)))) → a1(b2(x1)) (34)
a1(b2(a1(b0(x1)))) → a1(b0(x1)) (35)
a1(b2(a1(b1(x1)))) → a1(b1(x1)) (36)
c1(b2(a1(b2(x1)))) → c1(b2(x1)) (37)
c1(b2(a1(b0(x1)))) → c1(b0(x1)) (38)
c1(b2(a1(b1(x1)))) → c1(b1(x1)) (39)
b1(b2(a1(b2(x1)))) → b1(b2(x1)) (40)
b1(b2(a1(b0(x1)))) → b1(b0(x1)) (41)
b1(b2(a1(b1(x1)))) → b1(b1(x1)) (42)
a0(c0(c2(x1))) → a2(a1(b0(c1(b2(a2(x1)))))) (43)
a0(c0(c0(x1))) → a2(a1(b0(c1(b2(a0(x1)))))) (44)
a0(c0(c1(x1))) → a2(a1(b0(c1(b2(a1(x1)))))) (45)
c0(c0(c2(x1))) → c2(a1(b0(c1(b2(a2(x1)))))) (46)
c0(c0(c0(x1))) → c2(a1(b0(c1(b2(a0(x1)))))) (47)
c0(c0(c1(x1))) → c2(a1(b0(c1(b2(a1(x1)))))) (48)
b0(c0(c2(x1))) → b2(a1(b0(c1(b2(a2(x1)))))) (49)
b0(c0(c0(x1))) → b2(a1(b0(c1(b2(a0(x1)))))) (50)
b0(c0(c1(x1))) → b2(a1(b0(c1(b2(a1(x1)))))) (51)

1.1.1.1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.

1.2 Closure Under Flat Contexts

Using the flat contexts

{c(☐), a(☐)}

We obtain the transformed TRS
c(a(a(a(x1)))) → c(c(c(a(x1)))) (16)
c(a(c(a(x1)))) → c(c(c(a(x1)))) (17)
c(c(a(c(x1)))) → c(a(a(c(x1)))) (18)
a(a(a(a(x1)))) → a(c(c(a(x1)))) (22)
a(a(c(a(x1)))) → a(c(c(a(x1)))) (23)
a(c(a(c(x1)))) → a(a(a(c(x1)))) (24)

1.2.1 Closure Under Flat Contexts

Using the flat contexts

{c(☐), a(☐)}

We obtain the transformed TRS
c(c(a(a(a(x1))))) → c(c(c(c(a(x1))))) (79)
c(c(a(c(a(x1))))) → c(c(c(c(a(x1))))) (80)
c(c(c(a(c(x1))))) → c(c(a(a(c(x1))))) (81)
c(a(a(a(a(x1))))) → c(a(c(c(a(x1))))) (82)
c(a(a(c(a(x1))))) → c(a(c(c(a(x1))))) (83)
c(a(c(a(c(x1))))) → c(a(a(a(c(x1))))) (84)
a(c(a(a(a(x1))))) → a(c(c(c(a(x1))))) (85)
a(c(a(c(a(x1))))) → a(c(c(c(a(x1))))) (86)
a(c(c(a(c(x1))))) → a(c(a(a(c(x1))))) (87)
a(a(a(a(a(x1))))) → a(a(c(c(a(x1))))) (88)
a(a(a(c(a(x1))))) → a(a(c(c(a(x1))))) (89)
a(a(c(a(c(x1))))) → a(a(a(a(c(x1))))) (90)

1.2.1.1 Semantic Labeling

The following interpretations form a model of the rules.

As carrier we take the set {0,...,3}. Symbols are labeled by the interpretation of their arguments using the interpretations (modulo 4):

[c(x1)] = 2x1 + 0
[a(x1)] = 2x1 + 1

We obtain the labeled TRS
a3(a3(a3(a3(a3(x1))))) → a1(a0(c2(c3(a3(x1))))) (91)
a3(a3(a3(a3(a1(x1))))) → a1(a0(c2(c3(a1(x1))))) (92)
a3(a3(a3(a1(a2(x1))))) → a1(a0(c2(c1(a2(x1))))) (93)
a3(a3(a3(a1(a0(x1))))) → a1(a0(c2(c1(a0(x1))))) (94)
a2(c3(a3(a3(a3(x1))))) → a0(c0(c2(c3(a3(x1))))) (95)
a2(c3(a3(a3(a1(x1))))) → a0(c0(c2(c3(a1(x1))))) (96)
a2(c3(a3(a1(a2(x1))))) → a0(c0(c2(c1(a2(x1))))) (97)
a2(c3(a3(a1(a0(x1))))) → a0(c0(c2(c1(a0(x1))))) (98)
c3(a3(a3(a3(a3(x1))))) → c1(a0(c2(c3(a3(x1))))) (99)
c3(a3(a3(a3(a1(x1))))) → c1(a0(c2(c3(a1(x1))))) (100)
c3(a3(a3(a1(a2(x1))))) → c1(a0(c2(c1(a2(x1))))) (101)
c3(a3(a3(a1(a0(x1))))) → c1(a0(c2(c1(a0(x1))))) (102)
c2(c3(a3(a3(a3(x1))))) → c0(c0(c2(c3(a3(x1))))) (103)
c2(c3(a3(a3(a1(x1))))) → c0(c0(c2(c3(a1(x1))))) (104)
c2(c3(a3(a1(a2(x1))))) → c0(c0(c2(c1(a2(x1))))) (105)
c2(c3(a3(a1(a0(x1))))) → c0(c0(c2(c1(a0(x1))))) (106)
a3(a1(a2(c3(a3(x1))))) → a1(a0(c2(c3(a3(x1))))) (107)
a3(a1(a2(c3(a1(x1))))) → a1(a0(c2(c3(a1(x1))))) (108)
a3(a1(a2(c1(a2(x1))))) → a1(a0(c2(c1(a2(x1))))) (109)
a3(a1(a2(c1(a0(x1))))) → a1(a0(c2(c1(a0(x1))))) (110)
a2(c1(a2(c3(a3(x1))))) → a0(c0(c2(c3(a3(x1))))) (111)
a2(c1(a2(c3(a1(x1))))) → a0(c0(c2(c3(a1(x1))))) (112)
a2(c1(a2(c1(a2(x1))))) → a0(c0(c2(c1(a2(x1))))) (113)
a2(c1(a2(c1(a0(x1))))) → a0(c0(c2(c1(a0(x1))))) (114)
c3(a1(a2(c3(a3(x1))))) → c1(a0(c2(c3(a3(x1))))) (115)
c3(a1(a2(c3(a1(x1))))) → c1(a0(c2(c3(a1(x1))))) (116)
c3(a1(a2(c1(a2(x1))))) → c1(a0(c2(c1(a2(x1))))) (117)
c3(a1(a2(c1(a0(x1))))) → c1(a0(c2(c1(a0(x1))))) (118)
c2(c1(a2(c3(a3(x1))))) → c0(c0(c2(c3(a3(x1))))) (119)
c2(c1(a2(c3(a1(x1))))) → c0(c0(c2(c3(a1(x1))))) (120)
c2(c1(a2(c1(a2(x1))))) → c0(c0(c2(c1(a2(x1))))) (121)
c2(c1(a2(c1(a0(x1))))) → c0(c0(c2(c1(a0(x1))))) (122)
a1(a2(c1(a2(c3(x1))))) → a3(a3(a1(a2(c3(x1))))) (123)
a1(a2(c1(a2(c1(x1))))) → a3(a3(a1(a2(c1(x1))))) (124)
a1(a2(c1(a0(c2(x1))))) → a3(a3(a1(a0(c2(x1))))) (125)
a1(a2(c1(a0(c0(x1))))) → a3(a3(a1(a0(c0(x1))))) (126)
a0(c2(c1(a2(c3(x1))))) → a2(c3(a1(a2(c3(x1))))) (127)
a0(c2(c1(a2(c1(x1))))) → a2(c3(a1(a2(c1(x1))))) (128)
a0(c2(c1(a0(c2(x1))))) → a2(c3(a1(a0(c2(x1))))) (129)
a0(c2(c1(a0(c0(x1))))) → a2(c3(a1(a0(c0(x1))))) (130)
c1(a2(c1(a2(c3(x1))))) → c3(a3(a1(a2(c3(x1))))) (131)
c1(a2(c1(a2(c1(x1))))) → c3(a3(a1(a2(c1(x1))))) (132)
c1(a2(c1(a0(c2(x1))))) → c3(a3(a1(a0(c2(x1))))) (133)
c1(a2(c1(a0(c0(x1))))) → c3(a3(a1(a0(c0(x1))))) (134)
c0(c2(c1(a2(c3(x1))))) → c2(c3(a1(a2(c3(x1))))) (135)
c0(c2(c1(a2(c1(x1))))) → c2(c3(a1(a2(c1(x1))))) (136)
c0(c2(c1(a0(c2(x1))))) → c2(c3(a1(a0(c2(x1))))) (137)
c0(c2(c1(a0(c0(x1))))) → c2(c3(a1(a0(c0(x1))))) (138)

1.2.1.1.1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c0(x1)] = x1 +
0
[c2(x1)] = x1 +
1
[c1(x1)] = x1 +
5
[c3(x1)] = x1 +
1
[a0(x1)] = x1 +
1
[a2(x1)] = x1 +
5
[a1(x1)] = x1 +
1
[a3(x1)] = x1 +
5
all of the following rules can be deleted.
a3(a3(a3(a3(a3(x1))))) → a1(a0(c2(c3(a3(x1))))) (91)
a3(a3(a3(a3(a1(x1))))) → a1(a0(c2(c3(a1(x1))))) (92)
a3(a3(a3(a1(a2(x1))))) → a1(a0(c2(c1(a2(x1))))) (93)
a3(a3(a3(a1(a0(x1))))) → a1(a0(c2(c1(a0(x1))))) (94)
a2(c3(a3(a3(a3(x1))))) → a0(c0(c2(c3(a3(x1))))) (95)
a2(c3(a3(a3(a1(x1))))) → a0(c0(c2(c3(a1(x1))))) (96)
a2(c3(a3(a1(a2(x1))))) → a0(c0(c2(c1(a2(x1))))) (97)
a2(c3(a3(a1(a0(x1))))) → a0(c0(c2(c1(a0(x1))))) (98)
c3(a3(a3(a3(a3(x1))))) → c1(a0(c2(c3(a3(x1))))) (99)
c3(a3(a3(a3(a1(x1))))) → c1(a0(c2(c3(a1(x1))))) (100)
c2(c3(a3(a3(a3(x1))))) → c0(c0(c2(c3(a3(x1))))) (103)
c2(c3(a3(a3(a1(x1))))) → c0(c0(c2(c3(a1(x1))))) (104)
c2(c3(a3(a1(a2(x1))))) → c0(c0(c2(c1(a2(x1))))) (105)
c2(c3(a3(a1(a0(x1))))) → c0(c0(c2(c1(a0(x1))))) (106)
a3(a1(a2(c3(a3(x1))))) → a1(a0(c2(c3(a3(x1))))) (107)
a3(a1(a2(c3(a1(x1))))) → a1(a0(c2(c3(a1(x1))))) (108)
a3(a1(a2(c1(a2(x1))))) → a1(a0(c2(c1(a2(x1))))) (109)
a3(a1(a2(c1(a0(x1))))) → a1(a0(c2(c1(a0(x1))))) (110)
a2(c1(a2(c3(a3(x1))))) → a0(c0(c2(c3(a3(x1))))) (111)
a2(c1(a2(c3(a1(x1))))) → a0(c0(c2(c3(a1(x1))))) (112)
a2(c1(a2(c1(a2(x1))))) → a0(c0(c2(c1(a2(x1))))) (113)
a2(c1(a2(c1(a0(x1))))) → a0(c0(c2(c1(a0(x1))))) (114)
c2(c1(a2(c3(a3(x1))))) → c0(c0(c2(c3(a3(x1))))) (119)
c2(c1(a2(c3(a1(x1))))) → c0(c0(c2(c3(a1(x1))))) (120)
c2(c1(a2(c1(a2(x1))))) → c0(c0(c2(c1(a2(x1))))) (121)
c2(c1(a2(c1(a0(x1))))) → c0(c0(c2(c1(a0(x1))))) (122)
c1(a2(c1(a2(c3(x1))))) → c3(a3(a1(a2(c3(x1))))) (131)
c1(a2(c1(a2(c1(x1))))) → c3(a3(a1(a2(c1(x1))))) (132)
c1(a2(c1(a0(c2(x1))))) → c3(a3(a1(a0(c2(x1))))) (133)
c1(a2(c1(a0(c0(x1))))) → c3(a3(a1(a0(c0(x1))))) (134)
c0(c2(c1(a2(c3(x1))))) → c2(c3(a1(a2(c3(x1))))) (135)
c0(c2(c1(a2(c1(x1))))) → c2(c3(a1(a2(c1(x1))))) (136)
c0(c2(c1(a0(c2(x1))))) → c2(c3(a1(a0(c2(x1))))) (137)
c0(c2(c1(a0(c0(x1))))) → c2(c3(a1(a0(c0(x1))))) (138)

1.2.1.1.1.1 String Reversal

Since only unary symbols occur, one can reverse all terms and obtains the TRS
a2(a1(a3(a3(c3(x1))))) → a2(c1(c2(a0(c1(x1))))) (139)
a0(a1(a3(a3(c3(x1))))) → a0(c1(c2(a0(c1(x1))))) (140)
a3(c3(a2(a1(c3(x1))))) → a3(c3(c2(a0(c1(x1))))) (141)
a1(c3(a2(a1(c3(x1))))) → a1(c3(c2(a0(c1(x1))))) (142)
a2(c1(a2(a1(c3(x1))))) → a2(c1(c2(a0(c1(x1))))) (143)
a0(c1(a2(a1(c3(x1))))) → a0(c1(c2(a0(c1(x1))))) (144)
c3(a2(c1(a2(a1(x1))))) → c3(a2(a1(a3(a3(x1))))) (145)
c1(a2(c1(a2(a1(x1))))) → c1(a2(a1(a3(a3(x1))))) (146)
c2(a0(c1(a2(a1(x1))))) → c2(a0(a1(a3(a3(x1))))) (147)
c0(a0(c1(a2(a1(x1))))) → c0(a0(a1(a3(a3(x1))))) (148)
c3(a2(c1(c2(a0(x1))))) → c3(a2(a1(c3(a2(x1))))) (149)
c1(a2(c1(c2(a0(x1))))) → c1(a2(a1(c3(a2(x1))))) (150)
c2(a0(c1(c2(a0(x1))))) → c2(a0(a1(c3(a2(x1))))) (151)
c0(a0(c1(c2(a0(x1))))) → c0(a0(a1(c3(a2(x1))))) (152)

1.2.1.1.1.1.1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the naturals
[c0(x1)] =
2
· x1 +
1
[c2(x1)] =
2
· x1 +
1
[c1(x1)] =
2
· x1 +
1
[c3(x1)] =
1
· x1 +
1
[a0(x1)] =
1
· x1 +
0
[a2(x1)] =
2
· x1 +
0
[a1(x1)] =
2
· x1 +
0
[a3(x1)] =
2
· x1 +
0
all of the following rules can be deleted.
a2(a1(a3(a3(c3(x1))))) → a2(c1(c2(a0(c1(x1))))) (139)
a0(a1(a3(a3(c3(x1))))) → a0(c1(c2(a0(c1(x1))))) (140)
a3(c3(a2(a1(c3(x1))))) → a3(c3(c2(a0(c1(x1))))) (141)
a1(c3(a2(a1(c3(x1))))) → a1(c3(c2(a0(c1(x1))))) (142)
a2(c1(a2(a1(c3(x1))))) → a2(c1(c2(a0(c1(x1))))) (143)
a0(c1(a2(a1(c3(x1))))) → a0(c1(c2(a0(c1(x1))))) (144)
c3(a2(c1(a2(a1(x1))))) → c3(a2(a1(a3(a3(x1))))) (145)
c1(a2(c1(a2(a1(x1))))) → c1(a2(a1(a3(a3(x1))))) (146)
c2(a0(c1(a2(a1(x1))))) → c2(a0(a1(a3(a3(x1))))) (147)
c0(a0(c1(a2(a1(x1))))) → c0(a0(a1(a3(a3(x1))))) (148)
c3(a2(c1(c2(a0(x1))))) → c3(a2(a1(c3(a2(x1))))) (149)
c1(a2(c1(c2(a0(x1))))) → c1(a2(a1(c3(a2(x1))))) (150)
c2(a0(c1(c2(a0(x1))))) → c2(a0(a1(c3(a2(x1))))) (151)
c0(a0(c1(c2(a0(x1))))) → c0(a0(a1(c3(a2(x1))))) (152)

1.2.1.1.1.1.1.1 String Reversal

Since only unary symbols occur, one can reverse all terms and obtains the TRS

There are no rules.

1.2.1.1.1.1.1.1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.