Certification Problem

Input (TPDB SRS_Relative/Waldmann_19/random-41)

The rewrite relation of the following TRS is considered.

a(a(b(x1))) c(b(c(x1))) (1)
b(c(b(x1))) a(b(c(x1))) (2)
a(a(b(x1))) c(a(b(x1))) (3)
a(c(b(x1))) c(c(c(x1))) (4)
c(a(c(x1))) c(b(b(x1))) (5)
b(a(b(x1))) c(c(b(x1))) (6)
c(b(c(x1))) c(c(b(x1))) (7)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Closure Under Flat Contexts

Using the flat contexts

{c(), b(), a()}

We obtain the transformed TRS
c(a(a(b(x1)))) c(c(b(c(x1)))) (8)
c(b(c(b(x1)))) c(a(b(c(x1)))) (9)
c(a(a(b(x1)))) c(c(a(b(x1)))) (10)
c(a(c(b(x1)))) c(c(c(c(x1)))) (11)
c(c(a(c(x1)))) c(c(b(b(x1)))) (12)
c(b(a(b(x1)))) c(c(c(b(x1)))) (13)
c(c(b(c(x1)))) c(c(c(b(x1)))) (14)
b(a(a(b(x1)))) b(c(b(c(x1)))) (15)
b(b(c(b(x1)))) b(a(b(c(x1)))) (16)
b(a(a(b(x1)))) b(c(a(b(x1)))) (17)
b(a(c(b(x1)))) b(c(c(c(x1)))) (18)
b(c(a(c(x1)))) b(c(b(b(x1)))) (19)
b(b(a(b(x1)))) b(c(c(b(x1)))) (20)
b(c(b(c(x1)))) b(c(c(b(x1)))) (21)
a(a(a(b(x1)))) a(c(b(c(x1)))) (22)
a(b(c(b(x1)))) a(a(b(c(x1)))) (23)
a(a(a(b(x1)))) a(c(a(b(x1)))) (24)
a(a(c(b(x1)))) a(c(c(c(x1)))) (25)
a(c(a(c(x1)))) a(c(b(b(x1)))) (26)
a(b(a(b(x1)))) a(c(c(b(x1)))) (27)
a(c(b(c(x1)))) a(c(c(b(x1)))) (28)

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(a1(b2(x1)))) a0(c1(b0(c2(x1)))) (29)
a2(a2(a1(b1(x1)))) a0(c1(b0(c1(x1)))) (30)
a2(a2(a1(b0(x1)))) a0(c1(b0(c0(x1)))) (31)
b2(a2(a1(b2(x1)))) b0(c1(b0(c2(x1)))) (32)
b2(a2(a1(b1(x1)))) b0(c1(b0(c1(x1)))) (33)
b2(a2(a1(b0(x1)))) b0(c1(b0(c0(x1)))) (34)
c2(a2(a1(b2(x1)))) c0(c1(b0(c2(x1)))) (35)
c2(a2(a1(b1(x1)))) c0(c1(b0(c1(x1)))) (36)
c2(a2(a1(b0(x1)))) c0(c1(b0(c0(x1)))) (37)
a1(b0(c1(b2(x1)))) a2(a1(b0(c2(x1)))) (38)
a1(b0(c1(b1(x1)))) a2(a1(b0(c1(x1)))) (39)
a1(b0(c1(b0(x1)))) a2(a1(b0(c0(x1)))) (40)
b1(b0(c1(b2(x1)))) b2(a1(b0(c2(x1)))) (41)
b1(b0(c1(b1(x1)))) b2(a1(b0(c1(x1)))) (42)
b1(b0(c1(b0(x1)))) b2(a1(b0(c0(x1)))) (43)
c1(b0(c1(b2(x1)))) c2(a1(b0(c2(x1)))) (44)
c1(b0(c1(b1(x1)))) c2(a1(b0(c1(x1)))) (45)
c1(b0(c1(b0(x1)))) c2(a1(b0(c0(x1)))) (46)
a2(a2(a1(b2(x1)))) a0(c2(a1(b2(x1)))) (47)
a2(a2(a1(b1(x1)))) a0(c2(a1(b1(x1)))) (48)
a2(a2(a1(b0(x1)))) a0(c2(a1(b0(x1)))) (49)
b2(a2(a1(b2(x1)))) b0(c2(a1(b2(x1)))) (50)
b2(a2(a1(b1(x1)))) b0(c2(a1(b1(x1)))) (51)
b2(a2(a1(b0(x1)))) b0(c2(a1(b0(x1)))) (52)
c2(a2(a1(b2(x1)))) c0(c2(a1(b2(x1)))) (53)
c2(a2(a1(b1(x1)))) c0(c2(a1(b1(x1)))) (54)
c2(a2(a1(b0(x1)))) c0(c2(a1(b0(x1)))) (55)
a2(a0(c1(b2(x1)))) a0(c0(c0(c2(x1)))) (56)
a2(a0(c1(b1(x1)))) a0(c0(c0(c1(x1)))) (57)
a2(a0(c1(b0(x1)))) a0(c0(c0(c0(x1)))) (58)
b2(a0(c1(b2(x1)))) b0(c0(c0(c2(x1)))) (59)
b2(a0(c1(b1(x1)))) b0(c0(c0(c1(x1)))) (60)
b2(a0(c1(b0(x1)))) b0(c0(c0(c0(x1)))) (61)
c2(a0(c1(b2(x1)))) c0(c0(c0(c2(x1)))) (62)
c2(a0(c1(b1(x1)))) c0(c0(c0(c1(x1)))) (63)
c2(a0(c1(b0(x1)))) c0(c0(c0(c0(x1)))) (64)
a0(c2(a0(c2(x1)))) a0(c1(b1(b2(x1)))) (65)
a0(c2(a0(c1(x1)))) a0(c1(b1(b1(x1)))) (66)
a0(c2(a0(c0(x1)))) a0(c1(b1(b0(x1)))) (67)
b0(c2(a0(c2(x1)))) b0(c1(b1(b2(x1)))) (68)
b0(c2(a0(c1(x1)))) b0(c1(b1(b1(x1)))) (69)
b0(c2(a0(c0(x1)))) b0(c1(b1(b0(x1)))) (70)
c0(c2(a0(c2(x1)))) c0(c1(b1(b2(x1)))) (71)
c0(c2(a0(c1(x1)))) c0(c1(b1(b1(x1)))) (72)
c0(c2(a0(c0(x1)))) c0(c1(b1(b0(x1)))) (73)
a1(b2(a1(b2(x1)))) a0(c0(c1(b2(x1)))) (74)
a1(b2(a1(b1(x1)))) a0(c0(c1(b1(x1)))) (75)
a1(b2(a1(b0(x1)))) a0(c0(c1(b0(x1)))) (76)
b1(b2(a1(b2(x1)))) b0(c0(c1(b2(x1)))) (77)
b1(b2(a1(b1(x1)))) b0(c0(c1(b1(x1)))) (78)
b1(b2(a1(b0(x1)))) b0(c0(c1(b0(x1)))) (79)
c1(b2(a1(b2(x1)))) c0(c0(c1(b2(x1)))) (80)
c1(b2(a1(b1(x1)))) c0(c0(c1(b1(x1)))) (81)
c1(b2(a1(b0(x1)))) c0(c0(c1(b0(x1)))) (82)
a0(c1(b0(c2(x1)))) a0(c0(c1(b2(x1)))) (83)
a0(c1(b0(c1(x1)))) a0(c0(c1(b1(x1)))) (84)
a0(c1(b0(c0(x1)))) a0(c0(c1(b0(x1)))) (85)
b0(c1(b0(c2(x1)))) b0(c0(c1(b2(x1)))) (86)
b0(c1(b0(c1(x1)))) b0(c0(c1(b1(x1)))) (87)
b0(c1(b0(c0(x1)))) b0(c0(c1(b0(x1)))) (88)
c0(c1(b0(c2(x1)))) c0(c0(c1(b2(x1)))) (89)
c0(c1(b0(c1(x1)))) c0(c0(c1(b1(x1)))) (90)
c0(c1(b0(c0(x1)))) c0(c0(c1(b0(x1)))) (91)

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 +
1/3
[c1(x1)] = x1 +
13/3
[c2(x1)] = x1 +
11/3
[b0(x1)] = x1 +
0
[b1(x1)] = x1 +
4
[b2(x1)] = x1 +
10/3
[a0(x1)] = x1 +
13/3
[a1(x1)] = x1 +
10/3
[a2(x1)] = x1 +
4
all of the following rules can be deleted.
a2(a2(a1(b2(x1)))) a0(c1(b0(c2(x1)))) (29)
a2(a2(a1(b1(x1)))) a0(c1(b0(c1(x1)))) (30)
a2(a2(a1(b0(x1)))) a0(c1(b0(c0(x1)))) (31)
b2(a2(a1(b2(x1)))) b0(c1(b0(c2(x1)))) (32)
b2(a2(a1(b1(x1)))) b0(c1(b0(c1(x1)))) (33)
b2(a2(a1(b0(x1)))) b0(c1(b0(c0(x1)))) (34)
c2(a2(a1(b2(x1)))) c0(c1(b0(c2(x1)))) (35)
c2(a2(a1(b1(x1)))) c0(c1(b0(c1(x1)))) (36)
c2(a2(a1(b0(x1)))) c0(c1(b0(c0(x1)))) (37)
b1(b0(c1(b2(x1)))) b2(a1(b0(c2(x1)))) (41)
b1(b0(c1(b1(x1)))) b2(a1(b0(c1(x1)))) (42)
b1(b0(c1(b0(x1)))) b2(a1(b0(c0(x1)))) (43)
c1(b0(c1(b2(x1)))) c2(a1(b0(c2(x1)))) (44)
c1(b0(c1(b1(x1)))) c2(a1(b0(c1(x1)))) (45)
c1(b0(c1(b0(x1)))) c2(a1(b0(c0(x1)))) (46)
b2(a2(a1(b2(x1)))) b0(c2(a1(b2(x1)))) (50)
b2(a2(a1(b1(x1)))) b0(c2(a1(b1(x1)))) (51)
b2(a2(a1(b0(x1)))) b0(c2(a1(b0(x1)))) (52)
c2(a2(a1(b2(x1)))) c0(c2(a1(b2(x1)))) (53)
c2(a2(a1(b1(x1)))) c0(c2(a1(b1(x1)))) (54)
c2(a2(a1(b0(x1)))) c0(c2(a1(b0(x1)))) (55)
a2(a0(c1(b2(x1)))) a0(c0(c0(c2(x1)))) (56)
a2(a0(c1(b1(x1)))) a0(c0(c0(c1(x1)))) (57)
a2(a0(c1(b0(x1)))) a0(c0(c0(c0(x1)))) (58)
b2(a0(c1(b2(x1)))) b0(c0(c0(c2(x1)))) (59)
b2(a0(c1(b1(x1)))) b0(c0(c0(c1(x1)))) (60)
b2(a0(c1(b0(x1)))) b0(c0(c0(c0(x1)))) (61)
c2(a0(c1(b2(x1)))) c0(c0(c0(c2(x1)))) (62)
c2(a0(c1(b1(x1)))) c0(c0(c0(c1(x1)))) (63)
c2(a0(c1(b0(x1)))) c0(c0(c0(c0(x1)))) (64)
a1(b2(a1(b2(x1)))) a0(c0(c1(b2(x1)))) (74)
a1(b2(a1(b1(x1)))) a0(c0(c1(b1(x1)))) (75)
a1(b2(a1(b0(x1)))) a0(c0(c1(b0(x1)))) (76)
b1(b2(a1(b2(x1)))) b0(c0(c1(b2(x1)))) (77)
b1(b2(a1(b1(x1)))) b0(c0(c1(b1(x1)))) (78)
b1(b2(a1(b0(x1)))) b0(c0(c1(b0(x1)))) (79)
c1(b2(a1(b2(x1)))) c0(c0(c1(b2(x1)))) (80)
c1(b2(a1(b1(x1)))) c0(c0(c1(b1(x1)))) (81)
c1(b2(a1(b0(x1)))) c0(c0(c1(b0(x1)))) (82)

1.1.1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
c0#(c1(b0(c0(x1)))) c0#(c0(c1(b0(x1)))) (92)
c0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (93)
c0#(c1(b0(c0(x1)))) b0#(x1) (94)
c0#(c1(b0(c1(x1)))) c0#(c0(c1(b1(x1)))) (95)
c0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (96)
c0#(c1(b0(c2(x1)))) c0#(c0(c1(b2(x1)))) (97)
c0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (98)
c0#(c2(a0(c0(x1)))) c0#(c1(b1(b0(x1)))) (99)
c0#(c2(a0(c0(x1)))) b0#(x1) (100)
c0#(c2(a0(c1(x1)))) c0#(c1(b1(b1(x1)))) (101)
c0#(c2(a0(c2(x1)))) c0#(c1(b1(b2(x1)))) (102)
b0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (103)
b0#(c1(b0(c0(x1)))) b0#(x1) (104)
b0#(c1(b0(c0(x1)))) b0#(c0(c1(b0(x1)))) (105)
b0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (106)
b0#(c1(b0(c1(x1)))) b0#(c0(c1(b1(x1)))) (107)
b0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (108)
b0#(c1(b0(c2(x1)))) b0#(c0(c1(b2(x1)))) (109)
b0#(c2(a0(c0(x1)))) b0#(x1) (110)
b0#(c2(a0(c0(x1)))) b0#(c1(b1(b0(x1)))) (111)
b0#(c2(a0(c1(x1)))) b0#(c1(b1(b1(x1)))) (112)
b0#(c2(a0(c2(x1)))) b0#(c1(b1(b2(x1)))) (113)
a0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (114)
a0#(c1(b0(c0(x1)))) b0#(x1) (115)
a0#(c1(b0(c0(x1)))) a0#(c0(c1(b0(x1)))) (116)
a0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (117)
a0#(c1(b0(c1(x1)))) a0#(c0(c1(b1(x1)))) (118)
a0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (119)
a0#(c1(b0(c2(x1)))) a0#(c0(c1(b2(x1)))) (120)
a0#(c2(a0(c0(x1)))) b0#(x1) (121)
a0#(c2(a0(c0(x1)))) a0#(c1(b1(b0(x1)))) (122)
a0#(c2(a0(c1(x1)))) a0#(c1(b1(b1(x1)))) (123)
a0#(c2(a0(c2(x1)))) a0#(c1(b1(b2(x1)))) (124)
a1#(b0(c1(b0(x1)))) c0#(x1) (125)
a1#(b0(c1(b0(x1)))) b0#(c0(x1)) (126)
a1#(b0(c1(b0(x1)))) a1#(b0(c0(x1))) (127)
a1#(b0(c1(b0(x1)))) a2#(a1(b0(c0(x1)))) (128)
a1#(b0(c1(b1(x1)))) b0#(c1(x1)) (129)
a1#(b0(c1(b1(x1)))) a1#(b0(c1(x1))) (130)
a1#(b0(c1(b1(x1)))) a2#(a1(b0(c1(x1)))) (131)
a1#(b0(c1(b2(x1)))) b0#(c2(x1)) (132)
a1#(b0(c1(b2(x1)))) a1#(b0(c2(x1))) (133)
a1#(b0(c1(b2(x1)))) a2#(a1(b0(c2(x1)))) (134)
a2#(a2(a1(b0(x1)))) a0#(c2(a1(b0(x1)))) (135)
a2#(a2(a1(b1(x1)))) a0#(c2(a1(b1(x1)))) (136)
a2#(a2(a1(b2(x1)))) a0#(c2(a1(b2(x1)))) (137)

1.1.1.1.1 Monotonic Reduction Pair Processor with Usable Rules

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c0(x1)] = x1 +
1
[c1(x1)] = x1 +
1
[c2(x1)] = x1 +
1
[b0(x1)] = x1 +
1
[b1(x1)] = x1 +
1
[b2(x1)] = x1 +
1
[a0(x1)] = x1 +
1
[a1(x1)] = x1 +
0
[a2(x1)] = x1 +
1
[c0#(x1)] = x1 +
0
[b0#(x1)] = x1 +
1
[a0#(x1)] = x1 +
1
[a1#(x1)] = x1 +
2
[a2#(x1)] = x1 +
2
together with the usable rules
a1(b0(c1(b2(x1)))) a2(a1(b0(c2(x1)))) (38)
a1(b0(c1(b1(x1)))) a2(a1(b0(c1(x1)))) (39)
a1(b0(c1(b0(x1)))) a2(a1(b0(c0(x1)))) (40)
a2(a2(a1(b2(x1)))) a0(c2(a1(b2(x1)))) (47)
a2(a2(a1(b1(x1)))) a0(c2(a1(b1(x1)))) (48)
a2(a2(a1(b0(x1)))) a0(c2(a1(b0(x1)))) (49)
a0(c2(a0(c2(x1)))) a0(c1(b1(b2(x1)))) (65)
a0(c2(a0(c1(x1)))) a0(c1(b1(b1(x1)))) (66)
a0(c2(a0(c0(x1)))) a0(c1(b1(b0(x1)))) (67)
b0(c2(a0(c2(x1)))) b0(c1(b1(b2(x1)))) (68)
b0(c2(a0(c1(x1)))) b0(c1(b1(b1(x1)))) (69)
b0(c2(a0(c0(x1)))) b0(c1(b1(b0(x1)))) (70)
c0(c2(a0(c2(x1)))) c0(c1(b1(b2(x1)))) (71)
c0(c2(a0(c1(x1)))) c0(c1(b1(b1(x1)))) (72)
c0(c2(a0(c0(x1)))) c0(c1(b1(b0(x1)))) (73)
a0(c1(b0(c2(x1)))) a0(c0(c1(b2(x1)))) (83)
a0(c1(b0(c1(x1)))) a0(c0(c1(b1(x1)))) (84)
a0(c1(b0(c0(x1)))) a0(c0(c1(b0(x1)))) (85)
b0(c1(b0(c2(x1)))) b0(c0(c1(b2(x1)))) (86)
b0(c1(b0(c1(x1)))) b0(c0(c1(b1(x1)))) (87)
b0(c1(b0(c0(x1)))) b0(c0(c1(b0(x1)))) (88)
c0(c1(b0(c2(x1)))) c0(c0(c1(b2(x1)))) (89)
c0(c1(b0(c1(x1)))) c0(c0(c1(b1(x1)))) (90)
c0(c1(b0(c0(x1)))) c0(c0(c1(b0(x1)))) (91)
(w.r.t. the implicit argument filter of the reduction pair), the pairs
c0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (93)
c0#(c1(b0(c0(x1)))) b0#(x1) (94)
c0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (96)
c0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (98)
c0#(c2(a0(c0(x1)))) b0#(x1) (100)
b0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (103)
b0#(c1(b0(c0(x1)))) b0#(x1) (104)
b0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (106)
b0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (108)
b0#(c2(a0(c0(x1)))) b0#(x1) (110)
a0#(c1(b0(c0(x1)))) c0#(c1(b0(x1))) (114)
a0#(c1(b0(c0(x1)))) b0#(x1) (115)
a0#(c1(b0(c1(x1)))) c0#(c1(b1(x1))) (117)
a0#(c1(b0(c2(x1)))) c0#(c1(b2(x1))) (119)
a0#(c2(a0(c0(x1)))) b0#(x1) (121)
a1#(b0(c1(b0(x1)))) c0#(x1) (125)
a1#(b0(c1(b0(x1)))) b0#(c0(x1)) (126)
a1#(b0(c1(b0(x1)))) a1#(b0(c0(x1))) (127)
a1#(b0(c1(b0(x1)))) a2#(a1(b0(c0(x1)))) (128)
a1#(b0(c1(b1(x1)))) b0#(c1(x1)) (129)
a1#(b0(c1(b1(x1)))) a1#(b0(c1(x1))) (130)
a1#(b0(c1(b1(x1)))) a2#(a1(b0(c1(x1)))) (131)
a1#(b0(c1(b2(x1)))) b0#(c2(x1)) (132)
a1#(b0(c1(b2(x1)))) a1#(b0(c2(x1))) (133)
a1#(b0(c1(b2(x1)))) a2#(a1(b0(c2(x1)))) (134)
a2#(a2(a1(b0(x1)))) a0#(c2(a1(b0(x1)))) (135)
a2#(a2(a1(b1(x1)))) a0#(c2(a1(b1(x1)))) (136)
a2#(a2(a1(b2(x1)))) a0#(c2(a1(b2(x1)))) (137)
and no rules could be deleted.

1.1.1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 3 components.