Displaying similar documents to “Nd-solid varieties”

On the solidity of general varieties of tree languages

Magnus Steinby (2012)

Discussiones Mathematicae - General Algebra and Applications

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For a class of hypersubstitutions 𝓚, we define the 𝓚-solidity of general varieties of tree languages (GVTLs) that contain tree languages over all alphabets, general varieties of finite algebras (GVFAs), and general varieties of finite congruences (GVFCs). We show that if 𝓚 is a so-called category of substitutions, a GVTL is 𝓚-solid exactly in case the corresponding GVFA, or the corresponding GVFC, is 𝓚-solid. We establish the solidity status of several known GVTLs with respect to...

M-solid generalized non-deterministic varieties

Somsak Lekkoksung (2016)

Discussiones Mathematicae General Algebra and Applications

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A generalized non-deterministic hypersubstitution is a mapping which maps operation symbols of type τ to the set of terms of the same type which does not necessarily preserve the arity. We apply the generalized non-deterministic hypersubstitution to an algebra of type τ and obtain a class of derived algebras of type τ. The generalized non-deterministic hypersubstitutions can be also applied to sets of equations of type τ. We obtain two closure operators which turn out to be a conjugate...

Tree algebra of sofic tree languages

Nathalie Aubrun, Marie-Pierre Béal (2014)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We consider the languages of finite trees called tree-shift languages which are factorial extensible tree languages. These languages are sets of factors of subshifts of infinite trees. We give effective syntactic characterizations of two classes of regular tree-shift languages: the finite type tree languages and the tree languages which are almost of finite type. Each class corresponds to a class of subshifts of trees which is invariant by conjugacy. For this goal, we define a tree algebra...

Nested Sibling Tree Automata

Françoise Gire, Jean-Marc Talbot (2009)

RAIRO - Theoretical Informatics and Applications

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In the XML standard, data are represented as unranked labeled ordered trees. Regular unranked tree automata provide a useful formalism for the validation of schemas enforcing regular structural constraints on XML documents. However some concrete application contexts need the expression of more general constraints than the regular ones. In this paper we propose a new framework in which context-free style structural constraints can be expressed and validated. This framework is characterized...

Hyperidentities in many-sorted algebras

Klaus Denecke, Somsak Lekkoksung (2009)

Discussiones Mathematicae - General Algebra and Applications

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The theory of hyperidentities generalizes the equational theory of universal algebras and is applicable in several fields of science, especially in computers sciences (see e.g. [2,1]). The main tool to study hyperidentities is the concept of a hypersubstitution. Hypersubstitutions of many-sorted algebras were studied in [3]. On the basis of hypersubstitutions one defines a pair of closure operators which turns out to be a conjugate pair. The theory of conjugate pairs of additive closure...

Learning tree languages from text

Henning Fernau (2007)

RAIRO - Theoretical Informatics and Applications

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We study the problem of learning regular tree languages from text. We show that the framework of function distinguishability, as introduced by the author in [ (2003) 1679–1711], can be generalized from the case of string languages towards tree languages. This provides a large source of identifiable classes of regular tree languages. Each of these classes can be characterized in various ways. Moreover, we present a generic inference algorithm with polynomial update...

Construction of tree automata from regular expressions

Dietrich Kuske, Ingmar Meinecke (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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Since recognizable tree languages are closed under the rational operations, every regular tree expression denotes a recognizable tree language. We provide an alternative proof to this fact that results in smaller tree automata. To this aim, we transfer Antimirov's partial derivatives from regular word expressions to regular tree expressions. For an analysis of the size of the resulting automaton as well as for algorithmic improvements, we also transfer the methods of Champarnaud and...

Construction of tree automata from regular expressions

Dietrich Kuske, Ingmar Meinecke (2011)

RAIRO - Theoretical Informatics and Applications

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Since recognizable tree languages are closed under the rational operations, every regular tree expression denotes a recognizable tree language. We provide an alternative proof to this fact that results in smaller tree automata. To this aim, we transfer Antimirov's partial derivatives from regular word expressions to regular tree expressions. For an analysis of the size of the resulting automaton as well as for algorithmic improvements, we also transfer the methods of Champarnaud...

Rational tree relations.

Raoult, Jean-Claude (1997)

Bulletin of the Belgian Mathematical Society - Simon Stevin

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