Certification Problem

Input (TPDB SRS_Standard/Waldmann_06_SRS/uni-5)

The rewrite relation of the following TRS is considered.

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

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
c#(c(x1)) c#(b(x1)) (4)
c#(c(x1)) b#(x1) (5)
c#(c(x1)) a#(c(b(x1))) (6)
b#(b(x1)) c#(x1) (7)
b#(b(x1)) c#(c(x1)) (8)
b#(b(x1)) c#(c(c(x1))) (9)
b#(b(x1)) c#(c(c(c(x1)))) (10)

1.1 Monotonic Reduction Pair Processor with Usable Rules

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c(x1)] = x1 +
0
[b(x1)] = x1 +
0
[a(x1)] = x1 +
0
[c#(x1)] = x1 +
1
[b#(x1)] = x1 +
1
[a#(x1)] = x1 +
0
together with the usable rules
a(a(x1)) x1 (1)
b(b(x1)) c(c(c(c(x1)))) (2)
c(c(x1)) a(c(b(x1))) (3)
(w.r.t. the implicit argument filter of the reduction pair), the pair
c#(c(x1)) a#(c(b(x1))) (6)
and no rules could be deleted.

1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.