Abstract
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 language | English |
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Title of host publication | Where Mathematics, Computer Science, Liguistics and Biology Meet |
Subtitle of host publication | Essays in honour of Gheorghe Păun |
Editors | Carlos Martin-Vide, Victor Mitrana |
Place of Publication | Dordrecht, The Netherlands |
Publisher | Kluwer |
Pages | 175-186 |
Number of pages | 12 |
ISBN (Electronic) | 978-94-015-9634-3 |
ISBN (Print) | 978-90-481-5607-8 |
DOIs | |
Publication status | Published - 2001 |