Certification Problem

Input (TPDB TRS_Standard/SK90/4.30)

The rewrite relation of the following TRS is considered.

f(nil) nil (1)
f(.(nil,y)) .(nil,f(y)) (2)
f(.(.(x,y),z)) f(.(x,.(y,z))) (3)
g(nil) nil (4)
g(.(x,nil)) .(g(x),nil) (5)
g(.(x,.(y,z))) g(.(.(x,y),z)) (6)

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#(.(x,.(y,z))) g#(.(.(x,y),z)) (7)
g#(.(x,nil)) g#(x) (8)
f#(.(nil,y)) f#(y) (9)
f#(.(.(x,y),z)) f#(.(x,.(y,z))) (10)

1.1 Dependency Graph Processor

The dependency pairs are split into 2 components.