Certification Problem
Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-3-num-146)
The rewrite relation of the following TRS is considered.
a(x1) |
→ |
x1 |
(1) |
a(b(x1)) |
→ |
a(c(b(b(a(a(x1)))))) |
(2) |
b(x1) |
→ |
x1 |
(3) |
c(c(x1)) |
→ |
x1 |
(4) |
Property / Task
Prove or disprove termination.Answer / Result
No.Proof (by AProVE @ termCOMP 2023)
1 Looping derivation
There is a looping derivation.
a b b →+ ε a b b a
The derivation can be derived as follows.
-
a b →+ a c b b a a:
This is an original rule (OC1).
-
a →+ ε:
This is an original rule (OC1).
-
a b →+ a c b b a:
The overlap closure is obtained from the following two overlap closures (OC2).
-
a b →+ a c b b a a
-
a →+ ε
-
b →+ ε:
This is an original rule (OC1).
-
a b →+ a c b a:
The overlap closure is obtained from the following two overlap closures (OC3).
-
a b →+ c b b a:
The overlap closure is obtained from the following two overlap closures (OC3).
-
a b b →+ a c b c b b a:
The overlap closure is obtained from the following two overlap closures (OC2).
-
a b →+ a c b a
-
a b →+ c b b a
-
a b b →+ a c c b b a:
The overlap closure is obtained from the following two overlap closures (OC3).
-
a b b →+ a c b c b b a
-
b →+ ε
-
c c →+ ε:
This is an original rule (OC1).
-
a b b →+ a b b a:
The overlap closure is obtained from the following two overlap closures (OC3).
-
a b b →+ a c c b b a
-
c c →+ ε