Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z026)

The rewrite relation of the following TRS is considered.

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

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
a#(b(b(x1))) a#(a(x1)) (3)
a#(b(b(x1))) a#(x1) (4)
a#(a(b(x1))) a#(x1) (5)

1.1 Reduction Pair Processor

Using the linear polynomial interpretation over the naturals
[a#(x1)] = 1 · x1
[b(x1)] = 1 + 1 · x1
[a(x1)] = 1 + 1 · x1
the pairs
a#(b(b(x1))) a#(a(x1)) (3)
a#(b(b(x1))) a#(x1) (4)
a#(a(b(x1))) a#(x1) (5)
could be deleted.

1.1.1 P is empty

There are no pairs anymore.