On the Notion of Uncontrollable Marking in Supervisory Control of Petri Nets

We show that the notion of uncontrollable marking commonly used in the literature on supervisory control theory of Petri nets is not sound, by means of a counter-example. We also show how the definition can be corrected and provide an adaptation of a decidability proof for the problem of checking controllability for specifications expressed as deterministic Petri net languages.