@article{ValkVidal-Naquet:Petri:Regular:1981,
    Abstract = {It is shown that the regularity problem for firing sequence sets of Petri nets is decidable. For the proof, new techniques to characterize unbounded places are introduced. In the class L0 of terminal languages of labelled Petri nets the regularity problem in undecidable. In addition some lower bounds for the undecidability of the equality problems in L0 and L are given. L0{$\lambda$} is shown to be not closed under complementation without reference to the reachability problem.},
    Author = {Valk, R{\"u}diger and Vidal-Naquet, Guy},
    File = {Petri nets and regular languages - Valk, Vidal-Naquet (0) (0) - a - a - d.pdf},
    ISSN = {0022-0000},
    Journal = {Journal of Computer and System Sciences},
    Number = {3},
    Pages = {299--325},
    Title = {Petri nets and regular languages},
    URL = {http://www.sciencedirect.com/science/article/pii/0022000081900672},
    Volume = {23},
    Year = {1981},
    bdsk-url-1 = {http://www.sciencedirect.com/science/article/pii/0022000081900672},
    bdsk-url-2 = {http://dx.doi.org/10.1016/0022-0000(81)90067-2},
    date-added = {2016-01-22 15:43:46 +0000},
    date-modified = {2016-03-24 15:47:59 +0000},
    doi = {10.1016/0022-0000(81)90067-2}
}

@article{ValkVidal-Naquet:Petri:Regular:1981, Abstract = {It is shown that the regularity problem for firing sequence sets of Petri nets is decidable. For the proof, new techniques to characterize unbounded places are introduced. In the class L0 of terminal languages of labelled Petri nets the regularity problem in undecidable. In addition some lower bounds for the undecidability of the equality problems in L0 and L are given. L0{$\lambda$} is shown to be not closed under complementation without reference to the reachability problem.}, Author = {Valk, R{\"u}diger and Vidal-Naquet, Guy}, File = {Petri nets and regular languages - Valk, Vidal-Naquet (0) (0) - a - a - d.pdf}, ISSN = {0022-0000}, Journal = {Journal of Computer and System Sciences}, Number = {3}, Pages = {299--325}, Title = {Petri nets and regular languages}, URL = {http://www.sciencedirect.com/science/article/pii/0022000081900672}, Volume = {23}, Year = {1981}, bdsk-url-1 = {http://www.sciencedirect.com/science/article/pii/0022000081900672}, bdsk-url-2 = {http://dx.doi.org/10.1016/0022-0000(81)90067-2}, date-added = {2016-01-22 15:43:46 +0000}, date-modified = {2016-03-24 15:47:59 +0000}, doi = {10.1016/0022-0000(81)90067-2} }