View-Based Tree-Language Rewritings for XML

2014 ◽  
pp. 270-289 ◽  
Author(s):  
Laks V. S. Lakshmanan ◽  
Alex Thomo
Keyword(s):  
Tree Language

PROPERTIES OF QUASI-RELABELING TREE BIMORPHISMS

2010 ◽  
Vol 21 (03) ◽  
pp. 257-276 ◽  
Author(s):  
ANDREAS MALETTI ◽  
CĂTĂLIN IONUŢ TÎRNĂUCĂ
Keyword(s):  
Cartesian Product ◽  
Canonical Representation ◽  
Finite Union ◽  
Top Down ◽  
Tree Language ◽  
Regular Tree ◽  
Fundamental Properties ◽  
Tree Transducers ◽  
Tree Languages ◽  
Context Free

The fundamental properties of the class QUASI of quasi-relabeling relations are investigated. A quasi-relabeling relation is a tree relation that is defined by a tree bimorphism (φ, L, ψ), where φ and ψ are quasi-relabeling tree homomorphisms and L is a regular tree language. Such relations admit a canonical representation, which immediately also yields that QUASI is closed under finite union. However, QUASI is not closed under intersection and complement. In addition, many standard relations on trees (e.g., branches, subtrees, v-product, v-quotient, and f-top-catenation) are not quasi-relabeling relations. If quasi-relabeling relations are considered as string relations (by taking the yields of the trees), then every Cartesian product of two context-free string languages is a quasi-relabeling relation. Finally, the connections between quasi-relabeling relations, alphabetic relations, and classes of tree relations defined by several types of top-down tree transducers are presented. These connections yield that quasi-relabeling relations preserve the regular and algebraic tree languages.

State Complexity of Regular Tree Languages for Tree Matching

2016 ◽  
Vol 27 (08) ◽  
pp. 965-979
Author(s):  
Sang-Ki Ko ◽  
Ha-Rim Lee ◽  
Yo-Sub Han
Keyword(s):  
The State ◽  
Top Down ◽  
Matching Problem ◽  
Tree Language ◽  
State Complexity ◽  
Regular Tree ◽  
Language L ◽  
Different Types ◽  
Tree Languages

We study the state complexity of regular tree languages for tree matching problem. Given a tree t and a set of pattern trees L, we can decide whether or not there exists a subtree occurrence of trees in L from the tree t by considering the new language L′ which accepts all trees containing trees in L as subtrees. We consider the case when we are given a set of pattern trees as a regular tree language and investigate the state complexity. Based on the sequential and parallel tree concatenation, we define three types of tree languages for deciding the existence of different types of subtree occurrences. We also study the deterministic top-down state complexity of path-closed languages for the same problem.

A generalized superposition of linear tree languages and products of linear tree languages

2018 ◽  
Vol 11 (04) ◽  
pp. 1850048
Author(s):  
Pongsakorn Kitpratyakul ◽  
Bundit Pibaljommee
Keyword(s):  
Green’S Relations ◽  
Linear Superposition ◽  
Tree Language ◽  
Regular Elements ◽  
Type Formula ◽  
Green's Relations ◽  
Tree Languages

A linear tree language of type [Formula: see text] is a set of linear terms, terms containing no multiple occurrences of the same variable, of that type. Instead of the usual generalized superposition of tree languages, we define the generalized linear superposition to deal with linear tree languages and study its properties. Using this superposition, we define the product of linear tree languages. This product is not associative on the collection of all linear tree languages, but it is associative on some subsets of this collection whose products of any element in the subsets are nonempty. We classify such subsets and study properties of the obtained semigroup especially idempotent elements, regular elements, and Green’s relations [Formula: see text] and [Formula: see text].

Operational State Complexity of Subtree-Free Regular Tree Languages

2016 ◽  
Vol 27 (06) ◽  
pp. 705-724
Author(s):  
Sang-Ki Ko ◽  
Hae-Sung Eom ◽  
Yo-Sub Han
Keyword(s):  
The State ◽  
Tree Automaton ◽  
Top Down ◽  
Tree Language ◽  
Worst Case ◽  
Bottom Up ◽  
State Complexity ◽  
Regular Tree ◽  
Tree Languages

We introduce subtree-free regular tree languages that are closely related to XML schemas and investigate the state complexity of basic operations on subtree-free regular tree languages. The state complexity of an operation for regular tree languages is the number of states that are sufficient and necessary in the worst-case for the minimal deterministic ranked tree automaton that accepts the tree language obtained from the operation. We establish the precise state complexity of (sequential, parallel) concatenation, (bottom-up, top-down) star, intersection and union for subtree-free regular tree languages.

scholarly journals Idempotent tree languages

2013 ◽  
Vol 46 (1) ◽  
pp. 1-14
Author(s):  
K. Denecke ◽  
N. Sarasit ◽  
S. L. Wismath
Keyword(s):  
Tree Language ◽  
Tree Languages ◽  
Fixed Type

AbstractA tree language of a fixed type

Fuzzy tree language recognizability

2010 ◽  
Vol 161 (5) ◽  
pp. 716-734 ◽  
Author(s):  
Symeon Bozapalidis ◽  
Olympia Louscou Bozapalidoy
Keyword(s):  
Tree Language

GRAMMATICAL INFERENCE FOR THE AUTOMATIC GENERATION OF VISUAL LANGUAGES

1999 ◽  
Vol 09 (04) ◽  
pp. 467-493 ◽  
Author(s):  
FILOMENA FERRUCCI ◽  
GIULIANA VITIELLO
Keyword(s):  
Structural Properties ◽  
Automatic Generation ◽  
Interesting Property ◽  
Visual Language ◽  
Target Language ◽  
Grammatical Inference ◽  
Inference Algorithm ◽  
Visual Languages ◽  
Tree Language

In this paper we address the problem of the automatic generation of visual languages from a sample set of visual sentences. We present an improvement of the inference module of the VLG system which was originally conceived for the generation of iconic languages [11]. With this extension any kind of visual languages, like diagrams and forms, can be considered. To this aim, we present an inference algorithm for the class of Boundary SR grammars. These grammars are a subclass of the SR grammars with the interesting property of confluence, which extends the concept of context-freeness to the case of nonlinear grammars. Moreover, in spite of the simplicity and naturalness of the formalism, the generative power of this class is sufficient to specify interesting visual languages. The inference algorithm exploits an elegant characterization of Boundary SR languages in terms of tree and string languages. More precisely, we show that a visual language is a Boundary SR language if and only if it can be defined as a regular tree language and a set of properly associated string languages. Based on this result, the problem of identifying structural properties in a diagrammatic visual sentence is brought back to the detection of structural properties in tree and string languages. The main advantage coming from the use of a grammatical inference technique in visual language specification is that the designer only needs to specify a set of visual sentences that he/she feels to sufficiently exemplify the intended target language.

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