NO Nontermination Proof

Nontermination Proof

by ttt2 (version ttt2 1.15)

Input

The rewrite relation of the following TRS is considered.

a(a(b(b(x0)))) → b(b(b(b(b(a(a(a(a(a(x0))))))))))

Proof

1 Loop

The following loop proves nontermination.

t0 = a(a(b(b(b(b(x9))))))
→ε b(b(b(b(b(a(a(a(a(a(b(b(x9))))))))))))
→1.1.1.1.1.1.1.1 b(b(b(b(b(a(a(a(b(b(b(b(b(a(a(a(a(a(x9))))))))))))))))))
= t2
where t2 = C[t0σ] and σ = {x9/b(a(a(a(a(a(x9))))))} and C = b(b(b(b(b(a(☐))))))