## A note on the equivalence problem of rational formal power series.(English)Zbl 0609.68055

It is shown that the equivalence problem for K-$$\Sigma$$-automata is undecidable for a commutative semiring K. This contrasts with the Equality Theorem of Eilenberg which implies that the problem is decidable if K is a field.

### MSC:

 68Q45 Formal languages and automata 16Y60 Semirings

### Keywords:

K-$$\Sigma$$-automata; commutative semiring
Full Text:

### References:

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