Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z094)

The rewrite relation of the following TRS is considered.

f(x1) n(c(c(x1))) (1)
c(f(x1)) f(c(c(x1))) (2)
c(c(x1)) c(x1) (3)
n(s(x1)) f(s(s(x1))) (4)
n(f(x1)) f(n(x1)) (5)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by NaTT @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
c#(f(x1)) c#(c(x1)) (6)
f#(x1) n#(c(c(x1))) (7)
n#(s(x1)) f#(s(s(x1))) (8)
f#(x1) c#(c(x1)) (9)
n#(f(x1)) n#(x1) (10)
c#(f(x1)) c#(x1) (11)
c#(f(x1)) f#(c(c(x1))) (12)
f#(x1) c#(x1) (13)
n#(f(x1)) f#(n(x1)) (14)

1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.