Certification Problem

Input (TPDB SRS_Standard/Zantema_04/z013)

The rewrite relation of the following TRS is considered.

g(c(x1)) g(f(c(x1))) (1)
g(f(c(x1))) g(f(f(c(x1)))) (2)
g(g(x1)) g(f(g(x1))) (3)
f(f(g(x1))) g(f(x1)) (4)

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.
g#(f(c(x1))) f#(f(c(x1))) (5)
g#(c(x1)) f#(c(x1)) (6)
f#(f(g(x1))) g#(f(x1)) (7)
g#(c(x1)) g#(f(c(x1))) (8)
g#(g(x1)) g#(f(g(x1))) (9)
g#(f(c(x1))) g#(f(f(c(x1)))) (10)
f#(f(g(x1))) f#(x1) (11)
g#(g(x1)) f#(g(x1)) (12)

1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.