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Monadic datalog and the expressive power of languages for web information extraction

Georg Gottlob, Christoph Koch
2002 Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '02  
Along the way, several other results on the complexity of query evaluation and query containment for monadic datalog over trees are established, and a simple normal form for this language is presented.  ...  In this paper, we first study monadic datalog over trees as a wrapping language.  ...  The results first announced in [Gottlob and Koch 2002a ] include a formal comparison of monadic datalog and Elog with other visual wrapping languages that have been proposed in the literature.  ... 
doi:10.1145/543613.543617 dblp:conf/pods/GottlobK02 fatcat:ao6t3msqc5ettmqjimucwbb6tu

Monadic datalog and the expressive power of languages for web information extraction

Georg Gottlob, Christoph Koch
2002 Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '02  
Along the way, several other results on the complexity of query evaluation and query containment for monadic datalog over trees are established, and a simple normal form for this language is presented.  ...  In this paper, we first study monadic datalog over trees as a wrapping language.  ...  The results first announced in [Gottlob and Koch 2002a ] include a formal comparison of monadic datalog and Elog with other visual wrapping languages that have been proposed in the literature.  ... 
doi:10.1145/543616.543617 fatcat:yti6oaakbbepbdwde7o6zwe37q

On the Expressive Power of Homomorphism Counts [article]

Albert Atserias, Phokion G. Kolaitis, Wei-Lin Wu
2021 arXiv   pre-print
Our results unveil striking differences between the expressive power of the left profile and the right profile.  ...  In this paper, we embark on a study of the restrictions of the right profile by investigating relaxations of isomorphism that can or cannot be captured by restricting the right profile to a fixed class  ...  Our main aim is to compare the expressive power of restrictions of the right profile vs. the expressive power of restrictions of the left profile.  ... 
arXiv:2101.12733v2 fatcat:bfdawka6czgyva224meh7qzur4

On the Expressive Power of Homomorphism Counts

Albert Atserias, Phokion G. Kolaitis, Wei-Lin Wu
2021 2021 36th Annual ACM/IEEE Symposium on Logic in Computer Science (LICS)  
Our results unveil striking differences between the expressive power of the left profile and the right profile.  ...  In this paper, we embark on a study of the restrictions of the right profile by investigating relaxations of isomorphism that can or cannot be captured by restricting the right profile to a fixed class  ...  Our main aim is to compare the expressive power of restrictions of the right profile vs. the expressive power of restrictions of the left profile.  ... 
doi:10.1109/lics52264.2021.9470543 fatcat:uggy6wokendr7nfynegj2zisje

Datalog±

Andrea Calì, Georg Gottlob, Thomas Lukasiewicz
2009 Proceedings of the 12th International Conference on Database Theory - ICDT '09  
We report on a recently introduced family of expressive extensions of Datalog, called Datalog ± , which is a new framework for representing ontological axioms in form of integrity constraints, and for  ...  In particular, we show that the DL-Lite family of description logics and F-Logic Lite are expressible in Datalog ± .  ...  INTRODUCTION In this paper, we survey the results of two recent works [9, 10] on a family of expressive extensions of Datalog, called Datalog ± , towards query answering over ontologies.  ... 
doi:10.1145/1514894.1514897 dblp:conf/icdt/CaliGL09 fatcat:6vfptak2onetzfpi65cjzxd4bq

On the expressive power of counting

Stéphane Grumbach, Christophe Tollu
1995 Theoretical Computer Science  
It is essential in the case of unordered structures. Our aim is to understand the expressive power gained with a limited counting ability.  ...  We investigate the expressive power of various extensions of first-order, inductive, and infinitary logic with counting quantifiers.  ...  Acknowledgements We are greatly indebted to Guy Fayolle for the collaboration on the proof of Theorem 5.3. We also thank Jianwen Su for comments on an earlier draft.  ... 
doi:10.1016/0304-3975(95)00026-s fatcat:vqzgtgau2ne65dtgzzv3hcbexu

A Temporal Datalog Primer

Livia Blasi
2022 International Conference on Extending Database Technology  
However, even considering a limited volume of published literature, it is a challenge to understand the expressive power of the involved languages, especially in the context of current ones, and even more  ...  and in particular in extending Datalog with Metric Temporal Logic (MTL), that led to several studies on various fragments of the proposed language DatalogMTL.  ... 
dblp:conf/edbt/Blasi22 fatcat:xv6liw5545hmthxx5eg3ruzvxy

Weighted monadic datalog

Torsten Stüber, Heiko Vogler
2008 Theoretical Computer Science  
Based on monadic datalog, we introduce the concept of weighted monadic datalog over unranked trees.  ...  Moreover, we prove that a query can be evaluated efficiently on an unranked tree provided that (i) S is commutative and the underlying datalog program is non-circular or (ii) S is a finite and commutative  ...  Acknowledgement The work of first author was partially supported by Deutsche Forschungsgemeinschaft, project DFG VO 1011/4-1.  ... 
doi:10.1016/j.tcs.2008.04.025 fatcat:fs5dcam4trfn5puwozqvcegm7e

Event choice datalog

Gianluigi Greco, Antonella Guzzo, Domenico Saccà, Francesco Scarcello
2004 Proceedings of the 6th ACM SIGPLAN international conference on Principles and practice of declarative programming - PPDP '04  
ev for short), provides a powerful mechanism to formulate queries on the evolution of a knowledge base, given a sequence of events envisioned to occur in the future.  ...  A comprehensive study of the computational complexity of answering DATALOG !ev queries is reported.  ...  P Computational Complexity We next study the computational complexity of a number of problems related to DATALOG !ev programs and queries.  ... 
doi:10.1145/1013963.1013989 dblp:conf/ppdp/GrecoGSS04 fatcat:zdmqky726bbxbdouxutfyy735a

Monadic Datalog Containment [chapter]

Michael Benedikt, Pierre Bourhis, Pierre Senellart
2012 Lecture Notes in Computer Science  
We use the machinery to present an important case of the MDL/UCQ containment problem that is in co-NEXPTIME, and a case that is in EXPTIME.  ...  We then present a general approach for getting tighter bounds on the complexity, based on analysis of the number of mappings of queries into tree-like instances.  ...  Bourhis is supported by EPSRC EP/G004021/1 (the Engineering and Physical Sciences Research Council, UK). Senellart is partly supported by ERC grant Webdam, agreement 226513.  ... 
doi:10.1007/978-3-642-31585-5_11 fatcat:gesfjmuemja6tagvnexl5lxazm

n-permutability and linear Datalog implies symmetric Datalog [article]

Alexandr Kazda
2017 arXiv   pre-print
However, once somebody obtains a characterization of linear Datalog, our result immediately gives a characterization of symmetric Datalog.  ...  At the moment, it is not known for which structures A will CSP( A) be solvable by a linear Datalog program.  ...  I'm grateful to Pascal Tesson for helping me understand first order reductions better and to Benoit Larose for pointing out an error in the definition of subdirect constraints in the preprint of this paper  ... 
arXiv:1508.05766v5 fatcat:7623pec3yzclhdy3oapz243dqa

Expressiveness within Sequence Datalog [article]

Heba Aamer, Jan Hidders, Jan Paredaens, Jan Van den Bussche
2022 arXiv   pre-print
These results paint a complete picture of the expressiveness relationships among all possible Sequence Datalog fragments that can be formed using the six features that we consider.  ...  Motivated by old and new applications, we investigate Datalog as a language for sequence databases.  ...  [35] may be compared to Corollary 3 of Bonner and Mecca [9] . In the present work, we study the relative expressiveness of query language features in the context of Sequence Datalog.  ... 
arXiv:2206.06754v1 fatcat:jb6xyx6unve5hkoknbf7ppt6cy

Datalog and description logics: Expressive power [chapter]

Marco Cadoli, Luigi Palopoli, Maurizio Lenzerini
1998 Lecture Notes in Computer Science  
This paper investigates the possibility of exploiting formal analysis tools developed in the database eld for the purpose of studying the expressive power of description logics augmented with rule-based  ...  We report a preliminary analysis on the expressive power of such hybrid languages. Two speci c languages coupling a terminological component with Horn rules are considered.  ...  Such a result has been generalized to other complexity classes and sets of logical formulae. Formal studies of expressive power of description logics have been recently pursued.  ... 
doi:10.1007/3-540-64823-2_16 fatcat:52exjirv4fevzjajms6jivmghy

Greedy Algorithms in Datalog [article]

Sergio Greco, Carlo Zaniolo
2003 arXiv   pre-print
In the design of algorithms, the greedy paradigm provides a powerful tool for solving efficiently classical computational problems, within the framework of procedural languages.  ...  However, expressing these algorithms within the declarative framework of logic-based languages has proven a difficult research challenge.  ...  Acknowledgement The authors would like to thank D. Saccà for many hepfull discussions and suggestions. The referees deserve credit for many improvements.  ... 
arXiv:cs/0312041v1 fatcat:b5ltj7vbzjcvzkf2f7iycpv2mu

Graph queries through datalog optimizations

K. Tuncay Tekle, Michael Gorbovitski, Yanhong A. Liu
2010 Proceedings of the 12th international ACM SIGPLAN symposium on Principles and practice of declarative programming - PPDP '10  
This paper describes the use of a powerful graph query language for querying programs, and a novel combination of transformations for generating efficient implementations of the queries.  ...  The language supports graph path expressions that allow convenient use of both vertices and edges of arbitrary kinds as well as additional global and local parameters in graph paths.  ...  An atom on the right side of a rule is called a hypothesis, and the atom on the left side is called the conclusion. Datalog can be extended with negation and constraints.  ... 
doi:10.1145/1836089.1836093 dblp:conf/ppdp/TekleGL10 fatcat:tpvvfgso4vhzdbldbqe7fa7ate
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