Varieties of recognizable tree series over fields

  • Authors:
  • Zoltán Fülöp;Magnus Steinby

  • Affiliations:
  • Department of Computer Science, University of Szeged, Árpád tér 2, H-6720 Szeged, Hungary;Department of Mathematics, University of Turku, FIN-20014 Turku, Finland

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2011

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Abstract

We introduce varieties of recognizable @S-tree series (K@S-VTS for short) over a field K and a ranked alphabet @S. Our variety theorem establishes a bijective correspondence between these K@S-VTSs and the varieties of finite-dimensional K@S-algebras (K@S-VFDA for short); a K@S-algebra is a K-vector space equipped with multilinear @S-operations. The link between K@S-VTSs and K@S-VFDAs is provided by the syntactic K@S-algebras of tree series. The most immediate predecessors of this study are Berstel's and Reutenauer's (1982) [2] work on tree series over fields, Reutenauer's (1980) [27] theory of varieties of string series, Bozapalidis' and his associates (1983, 1989, 1991) [8,5,4] work on syntactic K@S-algebras, Steinby's (1979, 1992) [30,31] theory of varieties of tree languages, and our previous work (2009) on series of general algebras and their syntactic K@S-algebras.