scholarly journals The Complexity of Circumscription in DLs

2009 ◽  
Vol 35 ◽  
pp. 717-773 ◽  
Author(s):  
P. A. Bonatti ◽  
C. Lutz ◽  
F. Wolter
Keyword(s):  
Description Logics ◽  
Default Logic ◽  
Order Logic ◽  
First Order Logic ◽  
First Order ◽  
Alternative Approach ◽  
Default Rules ◽  
Logic Description ◽  
Interesting Alternative ◽  
Natural Way

As fragments of first-order logic, Description logics (DLs) do not provide nonmonotonic features such as defeasible inheritance and default rules. Since many applications would benefit from the availability of such features, several families of nonmonotonic DLs have been developed that are mostly based on default logic and autoepistemic logic. In this paper, we consider circumscription as an interesting alternative approach to nonmonotonic DLs that, in particular, supports defeasible inheritance in a natural way. We study DLs extended with circumscription under different language restrictions and under different constraints on the sets of minimized, fixed, and varying predicates, and pinpoint the exact computational complexity of reasoning for DLs ranging from ALC to ALCIO and ALCQO. When the minimized and fixed predicates include only concept names but no role names, then reasoning is complete for NExpTime^NP. It becomes complete for NP^NExpTime when the number of minimized and fixed predicates is bounded by a constant. If roles can be minimized or fixed, then complexity ranges from NExpTime^NP to undecidability.

V940: Pre-Pubic SPARC for Stress Urinary Incontinence: An Alternative Approach for Scarred Retzius Space

2004 ◽  
Vol 171 (4S) ◽  
pp. 249-249
Author(s):  
Paulo Palma ◽  
Cassio Riccetto ◽  
Marcelo Thiel ◽  
Miriam Dambros ◽  
Rogerio Fraga ◽  
...  
Keyword(s):  
Urinary Incontinence ◽  
Stress Urinary Incontinence ◽  
Alternative Approach

An alternative approach to treating delinquent youth

1986 ◽  
Vol 3 (3) ◽  
pp. 65-85
Author(s):  
Donald E. Weber ◽  
William H. Burke
Keyword(s):  
Delinquent Youth ◽  
Alternative Approach

Exit Surveys: Evaluation of an Alternative Approach

2011 ◽  
Author(s):  
Elizabeth M. Lentz ◽  
Chris Kubisiak ◽  
Peter Legree ◽  
Kristen Horgen ◽  
Mark C. Young ◽  
...  
Keyword(s):  
Alternative Approach
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