Filters








28,435 Hits in 5.6 sec

Partially Ordered Regular Languages for Graph Queries [chapter]

Sergio Flesca, Sergio Greco
1999 Lecture Notes in Computer Science  
In this paper we present an extension of regular languages to support graph queries. The proposed extension is based on the introduction of a partial order on the strings of the languages.  ...  Finally, we present an application of partially ordered languages for searching the Web.  ...  sets of partially ordered regular strings; • results on the complexity of and algorithms for graph searching by means of partially ordered path queries.  ... 
doi:10.1007/3-540-48523-6_29 fatcat:ccxebteq3ndv7peuqq554ayb6i

Partially ordered regular languages for graph queries

Sergio Flesca, Sergio Greco
2005 Journal of computer and system sciences (Print)  
In this paper we present an extension of regular languages to support graph queries. The proposed extension is based on the introduction of a partial order on the strings of the languages.  ...  Finally, we present an application of partially ordered languages for searching the Web.  ...  sets of partially ordered regular strings; • results on the complexity of and algorithms for graph searching by means of partially ordered path queries.  ... 
doi:10.1016/j.jcss.2003.04.003 fatcat:odwnxcj7yjgubdeozle3h2v4zy

New Rewritings and Optimizations for Regular Path Queries [chapter]

Gösta Grahne, Alex Thomo
2002 Lecture Notes in Computer Science  
All the languages for querying semistructured data and the web use as an integral part regular expressions.  ...  Also, we present query answering algorithms that utilize exact partial rewritings for regular path queries and conjunctive regular path queries respectively.  ...  Virtually, all the query languages for semi-structured data provide the possibility for the user to query the database through regular expressions.  ... 
doi:10.1007/3-540-36285-1_16 fatcat:7kkc5ilowzc43au4pxoj5nvpaa

Querying RDF Data from a Graph Database Perspective [chapter]

Renzo Angles, Claudio Gutierrez
2005 Lecture Notes in Computer Science  
We concentrate on query languages, analyze current RDF trends, and propose the incorporation to RDF query languages of primitives which are not present today, based on the experience and techniques of  ...  graph database research. 10  ...  With this objective, Flesca and Greco [FG99] introduce partially ordered regular languages based on some order on the nodes.  ... 
doi:10.1007/11431053_24 fatcat:gia7gzrs2jhjdlecw3vvexop6y

Expressive languages for selecting groups from graph-structured data

Vitaliy Liptchinsky, Benjamin Satzger, Rostyslav Zabolotnyi, Schahram Dustdar
2013 Proceedings of the 22nd international conference on World Wide Web - WWW '13  
Many query languages for graph-structured data are based on regular path expressions, which describe relations among pairs of nodes.  ...  We present an efficient algorithm for evaluating group queries in polynomial time from an input data graph.  ...  Today, SPARQL [33] , the W3C 1 query language for RDF [27] , is probably the most widely known query language for graph-structured data.  ... 
doi:10.1145/2488388.2488455 dblp:conf/www/LiptchinskySZD13 fatcat:s34wm4bgm5hvhk5xo5ptv77vfm

Type inference for queries on semistructured data

Tova Milo, Dan Suciu
1999 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '99  
We study the problem of type checking and type inference for queries over semistructured data.  ...  Introducing a novel traces technique, we show that the problem is difficult in general (NP-complete), but can be solved in PTIME for many practical cases, including, in particular, queries over XML data  ...  (S) is a regular language, for which a regul,ar expression can be constructed in polynomial time from S.  ... 
doi:10.1145/303976.303998 dblp:conf/pods/MiloS99 fatcat:x323vhzoyrg4lb6jg4oamupcxu

Algebraic rewritings for optimizing regular path queries

Gösta Grahne, Alex Thomo
2003 Theoretical Computer Science  
In this paper we focus on extracting as much information as possible from algebraic rewritings for the purpose of optimizing regular path queries.  ...  We give two algorithms for utilizing the partial lower and partial possibility rewritings to decrease the number of secondary memory accesses.  ...  Almost all the query languages for semi-structured data provide the possibility for the user to query the database through regular expressions.  ... 
doi:10.1016/s0304-3975(02)00739-9 fatcat:2admtbcddfa7hgveflke4fl2e4

Algebraic Rewritings for Optimizing Regular Path Queries [chapter]

Gösta Grahne, Alex Thomo
2001 Lecture Notes in Computer Science  
In this paper we focus on extracting as much information as possible from algebraic rewritings for the purpose of optimizing regular path queries.  ...  We give two algorithms for utilizing the partial lower and partial possibility rewritings to decrease the number of secondary memory accesses.  ...  Almost all the query languages for semi-structured data provide the possibility for the user to query the database through regular expressions.  ... 
doi:10.1007/3-540-44503-x_19 fatcat:rcoexmacgjcabenfy323ns3gk4

Subpath Queries on Compressed Graphs: a Survey [article]

Nicola Prezza
2020 arXiv   pre-print
This survey is a gentle introduction to the main landmarks of the fascinating journey that took us from suffix trees to today's compressed indexes for labeled graphs and regular languages.  ...  allowing to index regular languages and promising to shed new light on problems such as regular expression matching.  ...  Right: Hasse diagram of a co-lexicographic partial order for the graph.  ... 
arXiv:2011.10008v2 fatcat:nbx6tdyurbfexkojuuyzmpr4wu

Temporal Logic To Query Semantic Graphs Using The Model Checking Method

Mahdi Gueffaz, Sylvain Rampacek, Christophe Nicolle
2012 Journal of Software  
SPARQL (Simple Protocol and RDF query Language) query language is the standard for querying the Semantic Web, but it has a lot of limitations.  ...  We present a first method of converting RDF (Resource Description Framework) graphs into NµSMV and PROMELA (Process Meta Language) languages in order to be checked with the temporal logic property and  ...  (Regular XPath) is a query language based on XPath (XML Path Language) [13, 14] .  ... 
doi:10.4304/jsw.7.7.1462-1472 fatcat:sblqu7ijknao7mx6mduspwawke

Subpath Queries on Compressed Graphs: A Survey

Nicola Prezza
2021 Algorithms  
This survey is a gentle introduction to the main landmarks of the fascinating journey that took us from suffix trees to today's compressed indexes for labeled graphs and regular languages.  ...  allowing to index regular languages and promising to shed new light on problems, such as regular expression matching.  ...  (Right) Hasse diagram of a colexicographic partial order for the graph.  ... 
doi:10.3390/a14010014 fatcat:leysuxakfbdofnnpjnh5xphzcq

Query containment and rewriting using views for regular path queries under constraints

Gösta Grahne, Alex Thomo
2003 Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '03  
Virtually, all the query languages for semi-structured data provide the possibility for the user to query the database through regular expressions.  ...  The design of query languages using regular path expressions is based on the observation that many of the recursive queries, which arise in practice, amount to graph traversals.  ...  However, navigating a database graph, in order to answer a regular path query, is still very expensive.  ... 
doi:10.1145/773153.773165 dblp:conf/pods/GrahneT03 fatcat:2t23wwjkfjdtvjqfrd6rplueuy

Identifying unrecognizable regular languages by queries [chapter]

Claudio Ferretti, Giancarlo Mauri
1994 Lecture Notes in Computer Science  
We describe a new technique useful in identifying a subclass of regular trace languages (de ned on a free partially commutative monoid).  ...  We extend an algorithm de ned by Dana Angluin in 1987 for DFA's and using equivalence and membership queries.  ...  , that de nes a language L which satis es our statement, by induction on the structure of the regular expression for T, using the properties stated for ordered strings over regular operations.  ... 
doi:10.1007/3-540-57868-4_72 fatcat:uu3n73sw6vespdguv7qo5odinu

Page 9238 of Mathematical Reviews Vol. , Issue 2001M [page]

2001 Mathematical Reviews  
partial fixpoints and for inflationary fixpoints.  ...  Summary: “We study regular first-order update logic (FUL), which is a variant of regular dynamic logic in which updates  ... 

Queries with incomplete answers over semistructured data

Yaron Kanza, Werner Nutt, Yehoshua Sagiv
1999 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '99  
However, any practical query language for semistructured data will need regular path expression.  ...  features of query languages for semistructured structured data models and query languages for them.  ... 
doi:10.1145/303976.303999 dblp:conf/pods/KanzaNS99 fatcat:qaayjlqspjfi5a3jesez7ah2b4
« Previous Showing results 1 — 15 out of 28,435 results