Certification Problem

Input (TPDB TRS_Standard/Secret_06_TRS/5)

The rewrite relation of the following TRS is considered.

a(a(y,0),0) y (1)
c(c(y)) y (2)
c(a(c(c(y)),x)) a(c(c(c(a(x,0)))),y) (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by ttt2 @ termCOMP 2023)

1 Rule Removal

Using the linear polynomial interpretation over (4 x 4)-matrices with strict dimension 1 over the naturals
[a(x1, x2)] =
1 0 0 0
0 0 0 1
0 0 1 0
0 1 0 0
· x1 +
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
· x2 +
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
[0] =
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
[c(x1)] =
1 0 0 0
0 0 0 1
0 0 1 0
0 1 0 0
· x1 +
1 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
all of the following rules can be deleted.
c(c(y)) y (2)

1.1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
c#(a(c(c(y)),x)) a#(x,0) (4)
c#(a(c(c(y)),x)) c#(a(x,0)) (5)
c#(a(c(c(y)),x)) c#(c(a(x,0))) (6)
c#(a(c(c(y)),x)) c#(c(c(a(x,0)))) (7)
c#(a(c(c(y)),x)) a#(c(c(c(a(x,0)))),y) (8)

1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.