Certification Problem

Input (TPDB SRS_Standard/Wenzel_16/abcabbcab-abbcabcabbca.srs)

The rewrite relation of the following TRS is considered.

a(b(c(a(b(b(c(a(b(x1))))))))) a(b(b(c(a(b(c(a(b(b(c(a(x1)))))))))))) (1)

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(b(c(a(b(b(c(a(b(x1)))))))))) c(a(b(b(c(a(b(c(a(b(b(c(a(x1))))))))))))) (2)
b(a(b(c(a(b(b(c(a(b(x1)))))))))) b(a(b(b(c(a(b(c(a(b(b(c(a(x1))))))))))))) (3)
a(a(b(c(a(b(b(c(a(b(x1)))))))))) a(a(b(b(c(a(b(c(a(b(b(c(a(x1))))))))))))) (4)

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(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (5)
a2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (6)
a2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (7)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (8)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (9)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (10)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (11)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (12)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (13)

1.1.1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c2(x1)] = x1 +
0
[b0(x1)] = x1 +
0
[b1(x1)] = x1 +
0
[b2(x1)] = x1 +
1
[a0(x1)] = x1 +
0
[a1(x1)] = x1 +
0
[a2(x1)] = x1 +
0
all of the following rules can be deleted.
a2(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (5)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (8)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b2(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a2(x1))))))))))))) (11)

1.1.1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a0(x1)) (14)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))) (15)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a0(x1)))))) (16)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (17)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(x1)) (18)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))) (19)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(x1)))))) (20)
c2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (21)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a0(x1)) (22)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))) (23)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a0(x1)))))) (24)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) b2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (25)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(x1)) (26)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))) (27)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(x1)))))) (28)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) b2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (29)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a0(x1)) (30)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))) (31)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a0(x1)))))) (32)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) a2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (33)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(x1)) (34)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))) (35)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(x1)))))) (36)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) a2#(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (37)

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
[c2(x1)] = x1 +
0
[b0(x1)] = x1 +
0
[b1(x1)] = x1 +
0
[b2(x1)] = x1 +
0
[a0(x1)] = x1 +
0
[a1(x1)] = x1 +
0
[a2(x1)] = x1 +
0
[c2#(x1)] = x1 +
0
[b2#(x1)] = x1 +
1
[a2#(x1)] = x1 +
1
together with the usable rules
a2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (6)
a2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) a2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (7)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (9)
b2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) b2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (10)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))))))) (12)
c2(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2(a1(b1(b0(c2(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))))))) (13)
(w.r.t. the implicit argument filter of the reduction pair), the pairs
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a0(x1)) (22)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))) (23)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a0(x1)))))) (24)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(x1)) (26)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))) (27)
b2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(x1)))))) (28)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a0(x1)) (30)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a0(x1))))))))) (31)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b0(x1)))))))))) c2#(a1(b1(b0(c2(a0(x1)))))) (32)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(x1)) (34)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b0(c2(a1(b1(b0(c2(a1(x1))))))))) (35)
a2#(a1(b0(c2(a1(b1(b0(c2(a1(b1(x1)))))))))) c2#(a1(b1(b0(c2(a1(x1)))))) (36)
and no rules could be deleted.

1.1.1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.