On the number of nonterminal symbols in unambiguous conjunctive grammars
DCFS'12 Proceedings of the 14th international conference on Descriptional Complexity of Formal Systems
Parsing Boolean grammars over a one-letter alphabet using online convolution
Theoretical Computer Science
Parsing by matrix multiplication generalized to Boolean grammars
Theoretical Computer Science
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Systems of equations of the form X i =φ i (X 1,…,X n ) (1≤ i ≤ n) are considered, in which the unknowns are sets of natural numbers. Expressions φ i may contain the operations of union, intersection and elementwise addition $S+T=\{m+n\mid m\in S$, n∈T}. A system with an EXPTIME-complete least solution is constructed in the paper through a complete arithmetization of EXPTIME-completeness. At the same time, it is established that least solutions of all such systems are in EXPTIME. The general membership problem for these equations is proved to be EXPTIME-complete. Among the consequences of the result is EXPTIME-completeness of the compressed membership problem for conjunctive grammars.