Certification Problem

Input (TPDB TRS_Outermost/Strategy_outermost_added_08/n001)

The rewrite relation of the following TRS is considered.

h(f(f(x))) h(f(g(f(x)))) (1)
f(g(f(x))) f(f(x)) (2)
The evaluation strategy is outermost

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by AProVE @ termCOMP 2023)

1 Loop

The following loop proves nontermination.

t0 = h(f(g(f(x'))))
h(f(f(x')))
h(f(g(f(x'))))
= t2
where t2 = t0σ and σ = {x'/x'}