Certification Problem

Input (TPDB TRS_Standard/Transformed_CSR_04/Ex24_Luc06_FR)

The rewrite relation of the following TRS is considered.

f(n__b,X,n__c) f(X,c,X) (1)
c b (2)
b n__b (3)
c n__c (4)
activate(n__b) b (5)
activate(n__c) c (6)
activate(X) X (7)

Property / Task

Prove or disprove termination.

Answer / Result

No.

Proof (by ttt2 @ termCOMP 2023)

1 Loop

The following loop proves nontermination.

t0 = f(c,c,c)
f(c,c,n__c)
f(b,c,n__c)
f(n__b,c,n__c)
f(c,c,c)
= t4
where t4 = t0