摘要
A concurrent system can be modeled by a Petri net. A live Petri net may have fro-zen tokens. It is showed that such tokens can be deleted if they are superfluous, and, whilethey are useful, can be defrozen if they became frozen due to unfair occurrences of tran-sitions, and, finaloy, some frozen tokens lead to more processes.
A concurrent system can be modeled by a Petri net. A live Petri net may have fro-zen tokens. It is showed that such tokens can be deleted if they are superfluous, and, whilethey are useful, can be defrozen if they became frozen due to unfair occurrences of tran-sitions, and, finaloy, some frozen tokens lead to more processes.
