Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z086)

The rewrite relation of the following TRS is considered.

a(a(x1)) c(b(x1)) (1)
b(b(x1)) c(a(x1)) (2)
c(c(x1)) b(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#(a(x1)) b#(x1) (4)
a#(a(x1)) c#(b(x1)) (5)
b#(b(x1)) a#(x1) (6)
b#(b(x1)) c#(a(x1)) (7)
c#(c(x1)) a#(x1) (8)
c#(c(x1)) b#(a(x1)) (9)

1.1 Subterm Criterion Processor

We use the projection to multisets
π(c#) = { 1 }
π(b#) = { 1 }
π(a#) = { 1 }
π(c) = { 1, 1 }
π(b) = { 1, 1 }
π(a) = { 1, 1 }
to remove the pairs:
a#(a(x1)) b#(x1) (4)
b#(b(x1)) a#(x1) (6)
c#(c(x1)) a#(x1) (8)

1.1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.