Certification Problem

Input (TPDB SRS_Standard/ICFP_2010/214011)

The rewrite relation of the following TRS is considered.

0(1(1(x1))) → 0(2(1(1(x1)))) (1)
0(1(1(x1))) → 0(0(2(1(1(x1))))) (2)
0(1(1(x1))) → 0(2(1(2(1(x1))))) (3)
0(1(1(x1))) → 2(1(0(2(1(x1))))) (4)
3(0(1(x1))) → 1(3(0(0(2(4(x1)))))) (5)
3(5(1(x1))) → 1(3(4(5(x1)))) (6)
3(5(1(x1))) → 2(4(5(3(1(x1))))) (7)
5(1(3(x1))) → 5(3(1(2(x1)))) (8)
0(1(0(1(x1)))) → 1(1(0(0(2(4(x1)))))) (9)
0(1(2(3(x1)))) → 3(1(5(0(2(x1))))) (10)
0(1(2(3(x1)))) → 0(3(1(2(1(1(x1)))))) (11)
0(1(4(1(x1)))) → 0(2(1(2(4(1(x1)))))) (12)
0(1(4(1(x1)))) → 4(0(0(2(1(1(x1)))))) (13)
0(1(5(1(x1)))) → 0(0(2(1(1(5(x1)))))) (14)
0(4(5(1(x1)))) → 0(1(3(4(5(x1))))) (15)
3(2(0(1(x1)))) → 1(3(0(2(4(5(x1)))))) (16)
3(5(1(1(x1)))) → 1(3(4(5(1(x1))))) (17)
3(5(1(1(x1)))) → 1(5(3(1(2(x1))))) (18)
3(5(1(3(x1)))) → 3(5(3(1(2(x1))))) (19)
3(5(4(1(x1)))) → 4(1(3(4(5(x1))))) (20)
5(1(2(3(x1)))) → 5(5(3(1(2(x1))))) (21)
5(2(0(1(x1)))) → 5(3(1(0(2(4(x1)))))) (22)
5(4(3(3(x1)))) → 3(1(3(4(5(x1))))) (23)
5(5(0(1(x1)))) → 1(0(2(4(5(5(x1)))))) (24)
0(1(2(0(1(x1))))) → 0(3(0(2(1(1(x1)))))) (25)
0(1(2(2(1(x1))))) → 0(2(1(2(1(3(x1)))))) (26)
0(3(0(5(1(x1))))) → 0(3(4(5(0(1(x1)))))) (27)
0(3(4(2(3(x1))))) → 0(5(3(4(3(2(x1)))))) (28)
0(3(5(4(1(x1))))) → 0(5(2(4(3(1(x1)))))) (29)
0(4(1(2(3(x1))))) → 0(3(2(4(5(1(x1)))))) (30)
0(4(1(2(3(x1))))) → 4(3(1(0(0(2(x1)))))) (31)
0(4(5(5(1(x1))))) → 2(4(5(5(0(1(x1)))))) (32)
0(5(1(0(1(x1))))) → 0(1(5(5(0(1(x1)))))) (33)
0(5(3(2(1(x1))))) → 0(0(2(5(3(1(x1)))))) (34)
3(0(1(2(3(x1))))) → 0(2(3(4(3(1(x1)))))) (35)
3(0(1(2(3(x1))))) → 1(1(3(3(0(2(x1)))))) (36)
3(0(1(2(3(x1))))) → 1(2(3(3(0(2(x1)))))) (37)
3(0(4(1(1(x1))))) → 0(0(1(3(4(1(x1)))))) (38)
3(2(4(1(3(x1))))) → 4(3(4(3(1(2(x1)))))) (39)
3(3(4(1(1(x1))))) → 1(3(4(5(3(1(x1)))))) (40)
3(3(5(1(1(x1))))) → 3(1(4(5(3(1(x1)))))) (41)
3(5(4(1(3(x1))))) → 1(4(5(3(1(3(x1)))))) (42)
3(5(4(4(1(x1))))) → 4(1(4(3(4(5(x1)))))) (43)
5(2(4(2(3(x1))))) → 3(2(4(5(3(2(x1)))))) (44)
5(4(2(0(1(x1))))) → 5(1(2(0(2(4(x1)))))) (45)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Closure Under Flat Contexts

Using the flat contexts

{5(☐), 4(☐), 3(☐), 2(☐), 1(☐), 0(☐)}

We obtain the transformed TRS

There are 270 ruless (increase limit for explicit display).

1.1 Semantic Labeling

The following interpretations form a model of the rules.

As carrier we take the set {0,...,5}. Symbols are labeled by the interpretation of their arguments using the interpretations (modulo 6):

[5(x1)] = 6x1 + 0
[4(x1)] = 6x1 + 1
[3(x1)] = 6x1 + 2
[2(x1)] = 6x1 + 3
[1(x1)] = 6x1 + 4
[0(x1)] = 6x1 + 5

We obtain the labeled TRS

There are 1620 ruless (increase limit for explicit display).

1.1.1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[50(x1)] = x1 +
0
[51(x1)] = x1 +
72
[52(x1)] = x1 +
5
[53(x1)] = x1 +
36
[54(x1)] = x1 +
42
[55(x1)] = x1 +
0
[40(x1)] = x1 +
0
[41(x1)] = x1 +
0
[42(x1)] = x1 +
2
[43(x1)] = x1 +
108
[44(x1)] = x1 +
41
[45(x1)] = x1 +
72
[30(x1)] = x1 +
109
[31(x1)] = x1 +
5
[32(x1)] = x1 +
73
[33(x1)] = x1 +
77
[34(x1)] = x1 +
0
[35(x1)] = x1 +
108
[20(x1)] = x1 +
16
[21(x1)] = x1 +
0
[22(x1)] = x1 +
72
[23(x1)] = x1 +
16
[24(x1)] = x1 +
0
[25(x1)] = x1 +
72
[10(x1)] = x1 +
0
[11(x1)] = x1 +
41
[12(x1)] = x1 +
1
[13(x1)] = x1 +
36
[14(x1)] = x1 +
7
[15(x1)] = x1 +
16
[00(x1)] = x1 +
108
[01(x1)] = x1 +
115
[02(x1)] = x1 +
108
[03(x1)] = x1 +
0
[04(x1)] = x1 +
113
[05(x1)] = x1 +
0
all of the following rules can be deleted.

There are 1620 ruless (increase limit for explicit display).

1.1.1.1 R is empty

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