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Algorithms for Generating an Armstrong Relation and Inferring Functional Dependencies in the Relational Datamodel

J. Demetrovics, V.D. Thi
1993 Computers and Mathematics with Applications  
The main purpose of this paper is to give some new combinatorial algorithms for generating an Armstrong relation from a given relation scheme S and inferring functional dependencies (FDs) which hold in  ...  We give a class of relations and relation schemes for which generating an Armstrong relation and inferring the FDs are solved in polynomial time.  ...  GENERATING AN ARMSTRONG RELATION AND INFERRING FUNCTIONAL DEPENDENCIES In this section, we construct two combinatorial algorithms for generating an Armstrong relation and inferring functional dependencies  ... 
doi:10.1016/0898-1221(93)90033-r fatcat:thp4s4whkrfgpmc2efkjfas3pa

Page 6231 of Mathematical Reviews Vol. , Issue 96j [page]

1996 Mathematical Reviews  
Summary: “The main purpose of this paper is to give some re- sults concerning algorithms for generating Armstrong relations and inferring functional dependencies (FDs for short).  ...  {For the entire collection see MR 96h:68002. } 96j:68053 68P15 Demetrovics, Janos (H-AOS-C; Budapest) ; Thi, Vu Duc [Vu Duc Thi] (H-AOS-C; Budapest) Some remarks on generating Armstrong and inferring functional  ... 

On Matrix Representations of Participation Constraints [chapter]

Sven Hartmann, Uwe Leck, Sebastian Link
2009 Lecture Notes in Computer Science  
Matrix representations, also known as Armstrong relations, have been studied in literature e.g. for functional dependencies and play an important role in example-based design and for the implication problem  ...  We discuss the existence of matrix representations for generalized and minimum participation constraints which are frequently used in database design and conceptual modelling.  ...  Armstrong [1] observed that closed sets of functional dependencies correspond to closure operations on the set Ω.  ... 
doi:10.1007/978-3-642-04947-7_10 fatcat:vrpw7efxe5anfimszlmbybcxzq

Page 6546 of Mathematical Reviews Vol. , Issue 87k [page]

1987 Mathematical Reviews  
The resulting relation r* on (U — Z)Z* manifests certain functional and multivalued dependencies related to those of r, as described in detail in the paper. W. W.  ...  In particular, a functional dependency is a 1-dependency. A numerical dependency is defined as a k-dependency for some k.  ... 

On Codd Families of Keys over Incomplete Relations

S. Hartmann, U. Leck, S. Link
2010 Computer journal  
While the problem of finding an Armstrong relation for a given key set is precisely exponential in general, our algorithm returns an Armstrong relation whose size is at most quadratic in the size of a  ...  Therefore, a key over partial relations enforces both uniqueness and totality of tuples on the attributes of the key.  ...  The first author was supported by a research grant of the Alfried Krupp von Bohlen and Halbach foundation, administered by the German Scholars organization.  ... 
doi:10.1093/comjnl/bxq073 fatcat:j7kz4tguhzaflm5tten5wxyeo4

The Dretske–Tooley–Armstrong theory of natural laws and the inference problem

Joan Page`s
2002 International Studies in the Philosophy of Science  
In this article I intend to show that the inference problem, one of the main objections raised against the anti-Humean theory of natural laws defended by Dretske, Tooley and Armstrong ("DTA theory" for  ...  Then I state a solution to the inference problem that assumes a local immanentistic view of universals, a partial de nition of the nomic necessitation relation as a relation of existential dependence,  ...  Some remarks are in order here.  ... 
doi:10.1080/0269859022000013319 fatcat:woggqyczbzhv3m2rxfurvs34te

Preference Functional Dependencies for Managing Choices [chapter]

Wilfred Ng
2006 Lecture Notes in Computer Science  
We also confirm the existence of Armstrong preference relations for PFDs, a fundamental result related to the practical use of PFDs in database design.  ...  The notion of user preference in database modeling has recently received much attention in advanced applications, such as personalization of e-services, since it captures the human wishes on querying and  ...  Functional Dependencies (FDs) [2] are essentially the kinds of equality generating dependencies.  ... 
doi:10.1007/11901181_12 fatcat:tbwzvgtpbndflcqijzxkpw5wqa

Axiomatisation of functional dependencies in incomplete relations

Mark Levene, George Loizou
1998 Theoretical Computer Science  
Incomplete relations are relations which contain null values, whose meaning is "value is at present unknown". Such relations give rise to two types of functional dependency (FD).  ...  Finally, we show that Armstrong relations exist for SFDs and WFDs. @ 1998-Elsevier Science B.V. All rights reserved  ...  Functional dependencies in relations which may be incomplete We now define Functional Dependencies (FDs) and their satisfaction in the context of incomplete information.  ... 
doi:10.1016/s0304-3975(98)80029-7 fatcat:bbbvg75penczlo2oe3ltonsic4

Normalization and axiomatization for numerical dependencies

John Grant, Jack Minker
1985 Information and Control  
We present a finite set of inference rules for numerical dependencies which is a generalization of the Armstrong axioms. We prove that this set is sound and complete for some special cases.  ...  We show how to use both horizontal and vertical decomposition to normalize a database schema which contains numerical dependencies.  ...  Here we prove that a generalization of the Armstrong rules is sound and complete for numerical dependencies for some special cases.  ... 
doi:10.1016/s0019-9958(85)80017-6 fatcat:s2cxp6pw7fbozpbrcpcwspctky


Janusz A. Pomykała
2002 Demonstratio Mathematica  
On the one hand functional and multivalued dependencies in RDB capture a large portion of the semantics of real world relations, but it has proved useful to consider also other classes of dependencies  ...  A generalization of this theory to dependencies in other information frames is an open problem. We propose here an attempt to solve it for frames based on similarity relations.  ...  In [22] it is proved that the axioms (inference rules) for functional dependency (Armstrong axioms) and for multivalued dependency are sound and complete.  ... 
doi:10.1515/dema-2002-0423 fatcat:d4bvxefxbnc6dajrl7bid3yb5y

Armstrong axioms and Boyce–Codd–Heath Normal Form under bag semantics

Henning Koehler, Sebastian Link
2010 Information Processing Letters  
The theory of functional dependencies is based on relations, i.e. sets of tuples. Over relations, the class of functional dependencies subsumes the class of keys.  ...  Over bags, keys and functional dependencies interact differently from how they interact over relations.  ...  Acknowledgements We would like to thank David Maier for informing us about the problem of the interaction of keys and FDs under bag semantics.  ... 
doi:10.1016/j.ipl.2010.06.002 fatcat:oeiu3446uzclniyisjbsxxndni

Some problems on the functional dependency related to armstrong relations in the relational datamodel

Vu Duc Thi
2016 Journal of Computer Science and Cybernetics  
In the paper, we give some results to combinatorial algorithms for functional dependency (FD for short) connecting the construction of Armstrong relations, relation schemes, the FD-relation implication  ...  problem, and the FD-relation equivalence problem.  ...  SOME PROBLEMS ON THE FUCTIONAL DEPENDENCY RELATED TO ARMSTRONG RELATIONS IN THE RELATIONAL DATAMODEL Denote N = {A E I: A :t= n {A' E I: A cA' }}.  ... 
doi:10.15625/1813-9663/14/1/7876 fatcat:xtpy7r5gxjgyjjjqiehms3opxu

Independence in Database Relations [chapter]

Juha Kontinen, Sebastian Link, Jouko Väänänen
2013 Lecture Notes in Computer Science  
A relation satisfies X ⊥ Y if for every X-value and every Y -value that occurs in the relation there is some tuple in the relation in which the X-value occurs together with the Y -value.  ...  We show how to construct Armstrong relations which satisfy an arbitrarily given set of independence atoms and violate every independence atom not implied by the given set.  ...  This research is supported by the Marsden Fund Council from Government funding, administered by the Royal Society of New Zealand, and grants 264917 and 251557 of the Academy of Finland.  ... 
doi:10.1007/978-3-642-39992-3_17 fatcat:wnaz3pqabffa3hmfjvdu2lhagm

Dense Families and Key Functions of Database Relation Instances [chapter]

Jouni Järvinen
2001 Lecture Notes in Computer Science  
In this paper dense families of database relations are introduced. We characterize dependencies and keys of relation instances in terms of dense families. Key functions are also introduced.  ...  We show that each dense family determines an isotone Boolean function which is the dual of the key function.  ...  A set of functional dependencies E is a cover of a relation r, if the set of functional dependencies which can be inferred from E by applying Armstrong axioms (AS1)-(AS3) equals F r .  ... 
doi:10.1007/3-540-44669-9_19 fatcat:tgaf7c3havho5jgrhpvoniiize

Complex Predication and the Metaphysics of Properties

Bryan Pickel
2014 Dialectica  
The argument explores a variety of accounts of complex predicates currently on offer and develops a number of themes from the work of Herbert Hochberg.  ...  This explanatory link might suggest that the existence and distribution of properties expressed by complex predicates are explained by the existence and distribution of a sparser base of properties.  ...  In order to generate enough functions, one already needs an abundant supply of relations in the background.  ... 
doi:10.1111/1746-8361.12060 fatcat:p6ur3tlxwnagfievgv4spus6r4
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