Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z025)

The rewrite relation of the following TRS is considered.

b(a(x1)) a(b(x1)) (1)
a(a(a(x1))) b(a(a(b(x1)))) (2)
b(b(b(b(x1)))) a(x1) (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[b(x1)] = x1 +
1
[a(x1)] = x1 +
3
all of the following rules can be deleted.
a(a(a(x1))) b(a(a(b(x1)))) (2)
b(b(b(b(x1)))) a(x1) (3)

1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
b#(a(x1)) b#(x1) (4)

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
[b(x1)] = x1 +
0
[a(x1)] = x1 +
1
[b#(x1)] = x1 +
0
together with the usable rule
b(a(x1)) a(b(x1)) (1)
(w.r.t. the implicit argument filter of the reduction pair), the pair
b#(a(x1)) b#(x1) (4)
and no rules could be deleted.

1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 0 components.