A Note on Hack’s Conjecture, Parikh Images of Matrix Languages and Multiset Grammars
نویسنده
چکیده
It is shown that Hack’s Conjecture on Petri nets implies that for every language generated by a matrix grammar (without appearance checking), there is a non-erasing matrix grammar generating a language of the same Parikh image. Is is also shown that in this case, the classes of multiset languages generated by arbitrary and monotone multiset grammars coincide.
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