Certification Problem
Input (TPDB TRS_Standard/SK90/2.24)
The rewrite relation of the following TRS is considered.
|
fib(0) |
→ |
0 |
(1) |
|
fib(s(0)) |
→ |
s(0) |
(2) |
|
fib(s(s(x))) |
→ |
+(fib(s(x)),fib(x)) |
(3) |
Property / Task
Prove or disprove termination.Answer / Result
Yes.Proof (by AProVE @ termCOMP 2023)
1 Rule Removal
Using the
| prec(0) |
= |
1 |
|
stat(0) |
= |
lex
|
| prec(s) |
= |
1 |
|
stat(s) |
= |
lex
|
| prec(+) |
= |
0 |
|
stat(+) |
= |
lex
|
| π(fib) |
= |
1 |
| π(0) |
= |
[] |
| π(s) |
= |
[1] |
| π(+) |
= |
[2,1] |
all of the following rules can be deleted.
|
fib(s(s(x))) |
→ |
+(fib(s(x)),fib(x)) |
(3) |
1.1 Rule Removal
Using the
Knuth Bendix order with w0 = 1 and the following precedence and weight functions
| prec(0) |
= |
1 |
|
weight(0) |
= |
1 |
|
|
|
| prec(fib) |
= |
0 |
|
weight(fib) |
= |
1 |
|
|
|
| prec(s) |
= |
2 |
|
weight(s) |
= |
1 |
|
|
|
all of the following rules can be deleted.
|
fib(0) |
→ |
0 |
(1) |
|
fib(s(0)) |
→ |
s(0) |
(2) |
1.1.1 R is empty
There are no rules in the TRS. Hence, it is terminating.