Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z096)

The rewrite relation of the following TRS is considered.

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

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by ttt2 @ termCOMP 2023)

1 Loop

The following loop proves nontermination.

t0 = a(a(b(b(b(b(x18))))))
b(b(b(b(b(a(a(a(a(a(b(b(x18))))))))))))
b(b(b(b(b(a(a(a(b(b(b(b(b(a(a(a(a(a(x18))))))))))))))))))
= t2
where t2 = C[t0σ] and σ = {x18/b(a(a(a(a(a(x18))))))} and C = b(b(b(b(b(a())))))