Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z044)

The rewrite relation of the following TRS is considered.

c(a(b(a(x1)))) → a(b(a(b(c(c(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 = c(a(b(a(b(a(b(a(x100))))))))
→ a(b(a(b(c(c(a(b(a(b(a(x100)))))))))))
→ a(b(a(b(c(a(b(a(b(c(c(a(b(a(x100))))))))))))))
→ a(b(a(b(c(a(b(a(b(c(a(b(a(b(c(c(a(x100)))))))))))))))))
→ a(b(a(b(c(a(b(a(b(a(b(a(b(c(c(a(b(c(c(a(x100))))))))))))))))))))
= t4
where t4 = C[t0σ] and σ = {x100/b(c(c(a(b(c(c(a(x100))))))))} and C = a(b(a(b(☐))))