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

1993
*
Computers and Mathematics with Applications
*

The main purpose of this paper is to give

doi:10.1016/0898-1221(93)90033-r
fatcat:thp4s4whkrfgpmc2efkjfas3pa
*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*...##
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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*...##
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On Matrix Representations of Participation Constraints
[chapter]

2009
*
Lecture Notes in Computer Science
*

Matrix representations, also known as

doi:10.1007/978-3-642-04947-7_10
fatcat:vrpw7efxe5anfimszlmbybcxzq
*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. ...##
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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. ...##
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On Codd Families of Keys over Incomplete Relations

2010
*
Computer journal
*

While the problem of finding an

doi:10.1093/comjnl/bxq073
fatcat:j7kz4tguhzaflm5tten5wxyeo4
*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. ...##
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The Dretske–Tooley–Armstrong theory of natural laws and the inference problem

2002
*
International Studies in the Philosophy of Science
*

In this article I intend to show that the

doi:10.1080/0269859022000013319
fatcat:woggqyczbzhv3m2rxfurvs34te
*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. ...##
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Preference Functional Dependencies for Managing Choices
[chapter]

2006
*
Lecture Notes in Computer Science
*

We also confirm the existence of

doi:10.1007/11901181_12
fatcat:tbwzvgtpbndflcqijzxkpw5wqa
*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*. ...##
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Axiomatisation of functional dependencies in incomplete relations

1998
*
Theoretical Computer Science
*

Incomplete

doi:10.1016/s0304-3975(98)80029-7
fatcat:bbbvg75penczlo2oe3ltonsic4
*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. ...##
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Normalization and axiomatization for numerical dependencies

1985
*
Information and Control
*

We present a finite set of

doi:10.1016/s0019-9958(85)80017-6
fatcat:s2cxp6pw7fbozpbrcpcwspctky
*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. ...##
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SIMILARITY IN RELATIONAL DATABASES AND IN INFORMATION SYSTEMS THEORY

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. ...

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

2010
*
Information Processing Letters
*

The theory of

doi:10.1016/j.ipl.2010.06.002
fatcat:oeiu3446uzclniyisjbsxxndni
*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. ...##
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Some problems on the functional dependency related to armstrong relations in the relational datamodel

2016
*
Journal of Computer Science and Cybernetics
*

In the paper, we give

doi:10.15625/1813-9663/14/1/7876
fatcat:xtpy7r5gxjgyjjjqiehms3opxu
*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' }}. ...##
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Independence in Database Relations
[chapter]

2013
*
Lecture Notes in Computer Science
*

A

doi:10.1007/978-3-642-39992-3_17
fatcat:wnaz3pqabffa3hmfjvdu2lhagm
*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. ...##
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Dense Families and Key Functions of Database Relation Instances
[chapter]

2001
*
Lecture Notes in Computer Science
*

In this paper dense families of database

doi:10.1007/3-540-44669-9_19
fatcat:tgaf7c3havho5jgrhpvoniiize
*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 . ...##
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Complex Predication and the Metaphysics of Properties

2014
*
Dialectica
*

The argument explores a variety of accounts of complex predicates currently

doi:10.1111/1746-8361.12060
fatcat:p6ur3tlxwnagfievgv4spus6r4
*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. ...
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