Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z003)

The rewrite relation of the following TRS is considered.

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

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
[d(x1)] = x1 +
1
[c(x1)] = x1 +
0
[b(x1)] = x1 +
0
[a(x1)] = x1 +
0
all of the following rules can be deleted.
c(d(x1)) a(b(c(a(x1)))) (3)

1.1 Dependency Pair Transformation

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

1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.