Certification Problem

Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-2-num-20)

The rewrite relation of the following TRS is considered.

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

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by AProVE @ termCOMP 2023)

1 Looping derivation

There is a looping derivation.

a a b a b a b a b a b a b+ ε a a b a b a b a b a b a b a

The derivation can be derived as follows.