Abstract
The k-adjacent derivations, which generate the k-adjacent languages, were introduced by Kleijn and Rozenberg as an intermediate rewriting process between context-free rewriting and EOL rewriting. In this paper, we study the generative power of the k-adjacent derivations, in continuation of the work of Gonczarowski and Shamir, and Dahlhaus and Gaifman. We show that these derivations generate languages which satisfy the following: 1. • for all k ⩾ 2, the family of the k-adjacent languages contains all EOL languages generated by expanding grammars (this is a generalization of the result of Dahlhaus and Gaifman where k = 2); 2. • for all k ⩾ 3, the family of the k-adjacent languages contains all ETOL languages generated by expanding grammars; 3. • for k > 2, ( k + l)-adjacency has the same generative power as k-adjacency if the productions right-hand sides are large enough; 4. • there are k-adjacent languages, k ⩾ 3, which are not ETOL.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.