Certification Problem

Input (TPDB TRS_Standard/SK90/2.16)

The rewrite relation of the following TRS is considered.

f(0) 1 (1)
f(s(x)) g(x,s(x)) (2)
g(0,y) y (3)
g(s(x),y) g(x,+(y,s(x))) (4)
+(x,0) x (5)
+(x,s(y)) s(+(x,y)) (6)
g(s(x),y) g(x,s(+(y,x))) (7)

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.
+#(x,s(y)) +#(x,y) (8)
g#(s(x),y) +#(y,s(x)) (9)
g#(s(x),y) g#(x,+(y,s(x))) (10)
g#(s(x),y) g#(x,s(+(y,x))) (11)
f#(s(x)) g#(x,s(x)) (12)
g#(s(x),y) +#(y,x) (13)

1.1 Dependency Graph Processor

The dependency pairs are split into 2 components.