Certification Problem
Input (TPDB TRS_Outermost/Mixed_outermost/even)
The rewrite relation of the following TRS is considered.
|
g(b) |
→ |
g(f(f(f(f(b))))) |
(1) |
|
f(f(b)) |
→ |
b |
(2) |
|
f(b) |
→ |
b |
(3) |
|
g(f(b)) |
→ |
c |
(4) |
The evaluation strategy is outermostProperty / Task
Prove or disprove termination.Answer / Result
No.Proof (by AProVE @ termCOMP 2023)
1 Loop
The following loop proves nontermination.
| t0
|
= |
g(f(f(f(f(b))))) |
|
→
|
g(f(f(b))) |
|
→
|
g(b) |
|
→
|
g(f(f(f(f(b))))) |
|
= |
t3
|
where t3 =
t0