Certification Problem

Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-3-num-541)

The rewrite relation of the following TRS is considered.

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

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.
a#(c(x1)) a#(a(x1)) (4)
a#(c(x1)) a#(x1) (5)

1.1 Reduction Pair Processor

Using the linear polynomial interpretation over the naturals
[a#(x1)] = x1
[a(x1)] = 2 + x1
[b(x1)] = -2 + x1
[c(x1)] = 2 + x1
the pair
a#(c(x1)) a#(x1) (5)
could be deleted.

1.1.1 Reduction Pair Processor

Using the linear polynomial interpretation over the rationals with delta = 16
[a#(x1)] = 0 + 4 · x1
[c(x1)] = 4 + 2 · x1
[a(x1)] = 0 + 2 · x1
[b(x1)] = 2 + 1/2 · x1
the pair
a#(c(x1)) a#(a(x1)) (4)
could be deleted.

1.1.1.1 P is empty

There are no pairs anymore.