Certification Problem

Input (TPDB SRS_Standard/Waldmann_07_size12/size-12-alpha-3-num-49)

The rewrite relation of the following TRS is considered.

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

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by ttt2 @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
a#(b(b(x1))) a#(x1) (4)
a#(b(b(x1))) a#(a(x1)) (5)

1.1 Reduction Pair Processor with Usable Rules

Using the linear polynomial interpretation over (2 x 2)-matrices with strict dimension 1 over the arctic semiring over the integers
[b(x1)] =
-∞ 1
0 0
· x1 +
0 -∞
0 -∞
[a#(x1)] =
0 0
-∞ -∞
· x1 +
0 -∞
-∞ -∞
[a(x1)] =
0 0
0 0
· x1 +
0 -∞
0 -∞
[c(x1)] =
-∞ -∞
-∞ -∞
· x1 +
0 -∞
-∞ -∞
together with the usable rules
a(x1) x1 (1)
a(x1) b(c(b(x1))) (2)
a(b(b(x1))) b(b(a(a(x1)))) (3)
(w.r.t. the implicit argument filter of the reduction pair), the pairs
a#(b(b(x1))) a#(x1) (4)
a#(b(b(x1))) a#(a(x1)) (5)
could be deleted.

1.1.1 P is empty

There are no pairs anymore.