Certification Problem
Input (TPDB TRS_Standard/Transformed_CSR_04/Ex1_GM99_FR)
The rewrite relation of the following TRS is considered.
|
f(n__a,n__b,X) |
→ |
f(X,X,X) |
(1) |
| c |
→ |
a |
(2) |
| c |
→ |
b |
(3) |
| a |
→ |
n__a |
(4) |
| b |
→ |
n__b |
(5) |
|
activate(n__a) |
→ |
a |
(6) |
|
activate(n__b) |
→ |
b |
(7) |
|
activate(X) |
→ |
X |
(8) |
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,b,c) |
|
→
|
f(c,n__b,c) |
|
→
|
f(a,n__b,c) |
|
→
|
f(n__a,n__b,c) |
|
→
|
f(c,c,c) |
|
= |
t5
|
where t5 =
t0