The Number of Occurrences of Letters Versus Their Distribution in Some E0L Languages

Department of Mathematics, Utrecht University, Utrecht-Uithof, The Netherlands
Information and Control 11/1974; 26:256-271. DOI: 10.1016/S0019-9958(74)91379-5
Source: DBLP

ABSTRACT A characterization theorem is given for a class of developmental languages. The theorem binds together the number of occurrences of letters in the words of the given language with the distribution of these letters.

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    ABSTRACT: Let Í \subseteq *.K has a long block property (with respect to II), abbreviated asLB-property, if there exists a functionf:N + N + such that for everyw K and every positive integerm the number of blocks of length at mostm inw is bounded byf(m). K has a clustered block property (with respect to II), abbreviated asCB-property, if there exists a positive integern o and a growing functiong:N + N + such that for everyw K and for every positive integerm the blocks of length at mostm can be covered by at mostn o segments of length at mostg(m).It is proved that aCB-property always implies aLB-property but not necessarily other way around. It is proved that an EOL language has aLB-property if and only if it has aCB-property.
    Theory of Computing Systems 11/1985; 18(1):207-235. DOI:10.1007/BF01699470 · 0.45 Impact Factor
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    ABSTRACT: In this paper we continue the study of selective substitution grammars which form a framework for most of the rewriting systems studied in the literature. The continuous grammars we study in this paper generalize the basic rewriting principle of context-free grammars and EOL systems. The paper studies the language generating power of continuous grammars.
    Information and Control 07/1980; 46(1):71-91. DOI:10.1016/S0019-9958(80)90492-1
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    ABSTRACT: In this paper we study systematically three basic classes of grammars incorporating parallel rewriting: Indian parallel grammars, Russian parallel grammars and L systems. In particular by extracting basic characteristics of these systems and combining them we introduce new classes of rewriting systems (ETOL[k] systems, ETOLIP systems and ETOLRP systems) Among others, some results on the combinatorial structure of Indian parallel languages and on the combinatorial structures of the new classes of languages are proved. As far as ETOL systems are concerned we prove that every ETOL language can be generated with a fixed (equal to 8) bounded degree of parallelism.
    Information and Control 02/1980; 44:134-163. DOI:10.1016/S0019-9958(80)90066-2


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