scholarly journals Fixpoint Semantics for Recursive SHACL

2021 ◽  
Vol 345 ◽  
pp. 41-47
Author(s):  
Bart Bogaerts ◽  
Maxime Jakubowski
Keyword(s):  
Fixpoint Semantics

A Fixpoint Semantics for Rule-Base Anomalies

2011 ◽  
pp. 265-276 ◽  
Author(s):  
Du Zhang
Keyword(s):  
Knowledge Base ◽  
Domain Knowledge ◽  
Intelligent System ◽  
Domain Analysis ◽  
Rule Base ◽  
Crucial Component ◽  
Formal Definitions ◽  
Fixpoint Semantics ◽  
Verification Process ◽  
And Performance

A crucial component of an intelligent system is its knowledge base that contains knowledge about a problem domain. Knowledge base development involves domain analysis, context space definition, ontological specification, and knowledge acquisition, codification and verification. Knowledge base anomalies can affect the correctness and performance of an intelligent system. In this chapter, we describe a fixpoint semantics for a knowledge base that is based on a multi-valued logic. We then use the fixpoint semantics to provide formal definitions for four types of knowledge base anomalies: inconsistency, redundancy, incompleteness, circularity. We believe such formal definitions of knowledge base anomalies will help pave the way for a more effective knowledge base verification process.

NESTED GUARDED HORN CLAUSES

1990 ◽  
Vol 01 (03) ◽  
pp. 249-263 ◽  
Author(s):  
MORENO FALASCHI ◽  
MAURIZIO GABBRIELLI ◽  
GIORGIO LEVI ◽  
MASAKI MURAKAMI
Keyword(s):  
Logic Programming ◽  
Operational Semantics ◽  
Horn Clauses ◽  
Fixpoint Semantics ◽  
New Feature ◽  
Definition Of

This paper defines a new concurrent logic language, Nested Guarded Horn Clauses (NGHC). The main new feature of the language is its concept of guard. In fact, an NGHC clause has several layers of (standard) guards. This syntactic innovation allows the definition of a complete (i.e. always applicable) set of unfolding rules and therefore of an unfolding semantics which is equivalent, with respect to the success set, to the operational semantics. A fixpoint semantics is also defined in the classic logic programming style and is proved equivalent to the unfolding one. Since it is possible to embed Flat GHC into NGHC, our method can be used to give a fixpoint semantics to FGHC as well.

scholarly journals Fixpoint semantics and simulation

2000 ◽  
Vol 238 (1-2) ◽  
pp. 275-311 ◽  
Author(s):  
Wim H. Hesselink ◽  
Albert Thijs
Keyword(s):  
Fixpoint Semantics

A FRAMEWORK FOR HANDLING LOGICAL INCONSISTENCIES IN THE FUSION OF BOOLEAN KNOWLEDGE BASES

2011 ◽  
Vol 05 (03) ◽  
pp. 323-334
Author(s):  
ÉRIC GRÉGOIRE ◽  
DU ZHANG
Keyword(s):  
Knowledge Base ◽  
Knowledge Bases ◽  
Global Knowledge ◽  
Fixpoint Semantics ◽  
Algorithmic Techniques

In this paper, a framework for fusing several Boolean knowledge bases together is presented. The focus is on detecting inconsistencies and overcoming them so that a consistent global knowledge base is obtained. The framework is based on two cornerstones: detecting inconsistencies using algorithmic techniques to compute minimally unsatisfiable sub-formulas, and adopting a logic-based weakening approach to restore consistency for the fused knowledge. The dynamics in the framework in terms of both model-theoretic and the fixpoint semantics is then investigated.

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