Certification Problem

Input (TPDB TRS_Standard/SK90/2.61)

The rewrite relation of the following TRS is considered.

f(j(x,y),y) g(f(x,k(y))) (1)
f(x,h1(y,z)) h2(0,x,h1(y,z)) (2)
g(h2(x,y,h1(z,u))) h2(s(x),y,h1(z,u)) (3)
h2(x,j(y,h1(z,u)),h1(z,u)) h2(s(x),y,h1(s(z),u)) (4)
i(f(x,h(y))) y (5)
i(h2(s(x),y,h1(x,z))) z (6)
k(h(x)) h1(0,x) (7)
k(h1(x,y)) h1(s(x),y) (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.
g#(h2(x,y,h1(z,u))) h2#(s(x),y,h1(z,u)) (9)
h2#(x,j(y,h1(z,u)),h1(z,u)) h2#(s(x),y,h1(s(z),u)) (10)
f#(j(x,y),y) k#(y) (11)
f#(j(x,y),y) g#(f(x,k(y))) (12)
f#(x,h1(y,z)) h2#(0,x,h1(y,z)) (13)
f#(j(x,y),y) f#(x,k(y)) (14)

1.1 Dependency Graph Processor

The dependency pairs are split into 2 components.