An Infinite Sequence of Full AFL-Structures, Each of Which Possesses an Infinite Hierarchy

Peter R.J. Asveld

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    We investigate different sets of operations on languages which result in corresponding algebraic structures, viz. in different types of full AFL’s (full Abstract Family of Languages). By iterating control on ETOL-systems we show that there exists an infinite sequence Cm(m⩾1) of classes of such algebraic structures (full AFL-structures): each class is a proper superset of the next class (Cm ⊃ Cm +1). In turn each class Cm contains a countably infinite hierarchy, i.e. a countably infinite chain of language families Km,n (n⩾1) such that (i) each Km,n is closed under the operations that determine C m and (ii) each K m,n is properly included in the next one: Km,n ⊂ Km,n+1.
    Original languageEnglish
    Place of PublicationEnschede
    PublisherCentre for Telematics and Information Technology (CTIT)
    Number of pages11
    Publication statusPublished - 1999

    Publication series

    NameCTIT Technical Report Series
    PublisherUniversity of Twente, CTIT
    ISSN (Print)1381-3625


    • HMI-SLT: Speech and Language Technology


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    • An Infinite Sequence of Full AFL-structures, Each of Which Possesses an Infinite Hierarchy

      Asveld, P. R. J., 2001, Where Mathematics, Computer Science, Liguistics and Biology Meet: Essays in honour of Gheorghe Păun. Martin-Vide, C. & Mitrana, V. (eds.). Dordrecht, The Netherlands: Kluwer, p. 175-186 12 p.

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