Certification Problem

Input (TPDB TRS_Standard/SK90/4.43)

The rewrite relation of the following TRS is considered.

+(x,0) x (1)
+(x,s(y)) s(+(x,y)) (2)
+(0,y) y (3)
+(s(x),y) s(+(x,y)) (4)
+(x,+(y,z)) +(+(x,y),z) (5)
f(g(f(x))) f(h(s(0),x)) (6)
f(g(h(x,y))) f(h(s(x),y)) (7)
f(h(x,h(y,z))) f(h(+(x,y),z)) (8)

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.
f#(g(f(x))) f#(h(s(0),x)) (9)
f#(h(x,h(y,z))) f#(h(+(x,y),z)) (10)
f#(h(x,h(y,z))) +#(x,y) (11)
+#(x,+(y,z)) +#(x,y) (12)
f#(g(h(x,y))) f#(h(s(x),y)) (13)
+#(x,s(y)) +#(x,y) (14)
+#(s(x),y) +#(x,y) (15)
+#(x,+(y,z)) +#(+(x,y),z) (16)

1.1 Dependency Graph Processor

The dependency pairs are split into 2 components.