Certification Problem

Input (TPDB TRS_Standard/AProVE_10/scnp)

The rewrite relation of the following TRS is considered.

f(s(x),y) f(x,s(x)) (1)
f(x,s(y)) f(y,x) (2)
f(c(x),y) f(x,s(x)) (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)] = 2 · x1 + 1 · x2
[s(x1)] = 1 + 2 · x1
[c(x1)] = 1 + 2 · x1
all of the following rules can be deleted.
f(s(x),y) f(x,s(x)) (1)
f(x,s(y)) f(y,x) (2)
f(c(x),y) f(x,s(x)) (3)

1.1 R is empty

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