Certification Problem

Input (TPDB SRS_Standard/Zantema_06/beans5)

The rewrite relation of the following TRS is considered.

b(a(a(x1))) a(b(c(x1))) (1)
c(a(x1)) a(c(x1)) (2)
c(b(x1)) b(a(x1)) (3)
a(a(x1)) a(b(a(x1))) (4)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
b#(a(a(x1))) a#(b(c(x1))) (5)
b#(a(a(x1))) b#(c(x1)) (6)
b#(a(a(x1))) c#(x1) (7)
c#(a(x1)) a#(c(x1)) (8)
c#(a(x1)) c#(x1) (9)
c#(b(x1)) b#(a(x1)) (10)
c#(b(x1)) a#(x1) (11)
a#(a(x1)) a#(b(a(x1))) (12)
a#(a(x1)) b#(a(x1)) (13)

1.1 Reduction Pair Processor

Using the linear polynomial interpretation over the naturals
[b#(x1)] = 1 · x1
[a(x1)] = 1 + 1 · x1
[a#(x1)] = 1 · x1
[b(x1)] = 1 · x1
[c(x1)] = 1 + 1 · x1
[c#(x1)] = 1 + 1 · x1
the pairs
b#(a(a(x1))) a#(b(c(x1))) (5)
b#(a(a(x1))) b#(c(x1)) (6)
b#(a(a(x1))) c#(x1) (7)
c#(a(x1)) a#(c(x1)) (8)
c#(a(x1)) c#(x1) (9)
c#(b(x1)) a#(x1) (11)
could be deleted.

1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.