Certification Problem
Input (TPDB TRS_Standard/Strategy_removed_CSR_05/Ex14_AEGL02)
The rewrite relation of the following TRS is considered.
|
from(X) |
→ |
cons(X,from(s(X))) |
(1) |
|
length(nil) |
→ |
0 |
(2) |
|
length(cons(X,Y)) |
→ |
s(length1(Y)) |
(3) |
|
length1(X) |
→ |
length(X) |
(4) |
Property / Task
Prove or disprove termination.Answer / Result
No.Proof (by ttt2 @ termCOMP 2023)
1 Loop
The following loop proves nontermination.
| t0
|
= |
from(X) |
|
→
|
cons(X,from(s(X))) |
|
= |
t1
|
where t1 =
C[t0σ]
and
σ =
{X/s(X)}
and
C = cons(X,☐)