Certification Problem

Input (TPDB SRS_Relative/Waldmann_19/random-137)

The rewrite relation of the following TRS is considered.

a(c(a(x1))) b(a(c(x1))) (1)
a(c(c(x1))) a(b(b(x1))) (2)
c(a(a(x1))) a(a(a(x1))) (3)
b(c(c(x1))) a(c(a(x1))) (4)
b(a(a(x1))) b(c(b(x1))) (5)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by matchbox @ termCOMP 2023)

1 Rule Removal

Using the matrix interpretations of dimension 1 with strict dimension 1 over the rationals with delta = 1
[c(x1)] = x1 +
1
[b(x1)] = x1 +
0
[a(x1)] = x1 +
1/2
all of the following rules can be deleted.
a(c(a(x1))) b(a(c(x1))) (1)
a(c(c(x1))) a(b(b(x1))) (2)
c(a(a(x1))) a(a(a(x1))) (3)

1.1 Dependency Pair Transformation

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

1.1.1 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 +
1
[b(x1)] = x1 +
1
[a(x1)] = x1 +
1
[b#(x1)] = x1 +
0
together with the usable rules
b(c(c(x1))) a(c(a(x1))) (4)
b(a(a(x1))) b(c(b(x1))) (5)
(w.r.t. the implicit argument filter of the reduction pair), the pair
b#(a(a(x1))) b#(x1) (6)
and no rules could be deleted.

1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 0 components.