Outlier detection for simple default theories

It was noted recently that the framework of default logics can be exploited for detecting outliers. Outliers are observations expressed by sets of literals that feature unexpected properties. These observations are not explicitly provided in input (as it happens with abduction) but, rather, they are...

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Bibliographic Details
Published in:Artificial intelligence Vol. 174; no. 15; pp. 1247 - 1253
Main Authors: Angiulli, Fabrizio, Ben-Eliyahu-Zohary, Rachel, Palopoli, Luigi
Format: Journal Article
Language:English
Published: Oxford Elsevier B.V 01.10.2010
Elsevier
Subjects:
Abduction
Algorithmics. Computability. Computer arithmetics
Applied sciences
Artificial intelligence
C (programming language)
Computational complexity
Computer science; control theory; systems
Data mining
Data processing. List processing. Character string processing
Default logic
Disjunctive logic programming
Exact sciences and technology
Expert systems
Formalism
Hierarchies
Knowledge bases (artificial intelligence)
Knowledge representation
Logic
Logic programming
Memory organisation. Data processing
Nonmonotonic reasoning
Outlier detection
Software
Theoretical computing
Disjunctive logic programming
Nonmonotonic reasoning
Knowledge representation
Outlier detection
Data mining
Computational complexity
Default logic
Data analysis
Knowledge base
Logical programming
Circumscription
Polynomial time
Outlier
Disjunctive programming
Abduction
ISSN:0004-3702, 1872-7921
Online Access:Get full text
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Summary:It was noted recently that the framework of default logics can be exploited for detecting outliers. Outliers are observations expressed by sets of literals that feature unexpected properties. These observations are not explicitly provided in input (as it happens with abduction) but, rather, they are hidden in the given knowledge base. Unfortunately, in the two related formalisms for specifying defaults — Reiter's default logic and extended disjunctive logic programs — the most general outlier detection problems turn out to lie at the third level of the polynomial hierarchy. In this note, we analyze the complexity of outlier detection for two very simple classes of default theories, namely NU and DNU, for which the entailment problem is solvable in polynomial time. We show that, for these classes, checking for the existence of an outlier is anyway intractable. This result contributes to further showing the inherent intractability of outlier detection in default reasoning.
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ISSN:0004-3702
1872-7921
DOI:10.1016/j.artint.2010.07.006