Certification Problem

Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-3-num-217)

The rewrite relation of the following TRS is considered.

a(x1) x1 (1)
a(b(x1)) b(b(c(a(x1)))) (2)
b(x1) x1 (3)
b(c(c(x1))) a(x1) (4)

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by AProVE @ termCOMP 2023)

1 Looping derivation

There is a looping derivation.

a b b b c b b+ ε a b b b c b b c a

The derivation can be derived as follows.