Certification Problem

Input (TPDB TRS_Standard/SK90/2.54)

The rewrite relation of the following TRS is considered.

f(x,a) x (1)
f(x,g(y)) f(g(x),y) (2)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(f) = 0 stat(f) = lex
prec(a) = 1 stat(a) = lex

π(f) = [1,2]
π(a) = []
π(g) = 1

all of the following rules can be deleted.
f(x,a) x (1)

1.1 Rule Removal

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

1.1.1 R is empty

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