Certification Problem

Input (TPDB TRS_Standard/Mixed_TRS/jones5)

The rewrite relation of the following TRS is considered.

f(x,empty) x (1)
f(empty,cons(a,k)) f(cons(a,k),k) (2)
f(cons(a,k),y) f(y,k) (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the linear polynomial interpretation over the naturals
[f(x1, x2)] = 1 · x1 + 2 · x2
[empty] = 2
[cons(x1, x2)] = 1 · x1 + 2 · x2
all of the following rules can be deleted.
f(x,empty) x (1)
f(empty,cons(a,k)) f(cons(a,k),k) (2)

1.1 Rule Removal

Using the Knuth Bendix order with w0 = 1 and the following precedence and weight functions
prec(cons) = 1 weight(cons) = 0
prec(f) = 0 weight(f) = 0
all of the following rules can be deleted.
f(cons(a,k),y) f(y,k) (3)

1.1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.