IMI/Publicaţii/CSJM/Ediţii/CSJM v.30, n.2 (89), 2022/

On Elimination of Erasing Rules from E0S Grammars

Authors: Alexander Meduna, Martin Havel
Keywords: Formal languages, E0S grammars, elimination of erasing rules.


The present paper describes an alternative algorithm for the removal of erasing rules from E0S grammars. As opposed to the standard way of eliminating erasing rules in most E0S-like grammars, such as context-free grammars, this method requires no predetermination of symbols that derive the empty string. The proposed algorithm is formally verified. In the conclusion of the paper, the applicability of the algorithm to E0S grammars that work in a semi-parallel way is demonstrated. Furthermore, two open problems are formulated.

Faculty of Information Technology, Brno University of Technology
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