Certification Problem

Input (TPDB TRS_Outermost/Strategy_outermost_added_08/Ex9_Luc04_Z)

The rewrite relation of the following TRS is considered.

f(a,n__b,X) f(X,X,X) (1)
c a (2)
c b (3)
b n__b (4)
activate(n__b) b (5)
activate(X) X (6)
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 = f(c,c,c)
f(c,b,c)
f(c,n__b,c)
f(a,n__b,c)
f(c,c,c)
= t4
where t4 = t0