Certification Problem

Input (TPDB SRS_Standard/Secret_06_SRS/multum5)

The rewrite relation of the following TRS is considered.

a(a(a(b(x1)))) → b(a(a(a(x1)))) (1)
b(b(x1)) → a(b(a(b(x1)))) (2)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 String Reversal

Since only unary symbols occur, one can reverse all terms and obtains the TRS
b(a(a(a(x1)))) → a(a(a(b(x1)))) (3)
b(b(x1)) → b(a(b(a(x1)))) (4)

1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
b#(b(x1)) → b#(a(x1)) (5)
b#(b(x1)) → b#(a(b(a(x1)))) (6)
b#(a(a(a(x1)))) → b#(x1) (7)

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 +
1
[a(x1)] = x1 +
0
[b#(x1)] = x1 +
0
together with the usable rules
b(a(a(a(x1)))) → a(a(a(b(x1)))) (3)
b(b(x1)) → b(a(b(a(x1)))) (4)
(w.r.t. the implicit argument filter of the reduction pair), the pair
b#(b(x1)) → b#(a(x1)) (5)
and no rules could be deleted.

1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.