77 research outputs found
Variations on a Theme: A Bibliography on Approaches to Theorem Proving Inspired From Satchmo
This articles is a structured bibliography on theorem provers,
approaches to theorem proving, and theorem proving applications inspired
from Satchmo, the model generation theorem prover developed
in the mid 80es of the 20th century at ECRC, the European Computer-
Industry Research Centre. Note that the bibliography given in this article
is not exhaustive
Proving Finite Satisfiability of Deductive Databases
It is shown how certain refutation methods can be extended into semi-decision
procedures that are complete for both unsatisfiability and finite satisfiability. The proposed extension
is justified by a new characterization of finite satisfiability. This research was motivated
by a database design problem: Deduction rules and integrity constraints in definite databases
have to be finitely satisfiabl
Reftections on sorne fundamental issues of rule-based incremental update propagation
This paper addresses two fundamental aspects of update propagation in deductive
databases:
1. How to incrementally compute the sets of updates induced by a deductive rule from
the changes of the data sets on which the rule depends? and
2. How to express such incremental definitions by meaos of deductive rules defining
induced updates?
Both problems have already been addressed by many authors in various contexts. The
motivation for coming up with yet another such paper comes from the impression that
sorne of the very basic assumptions and justifications of the approaches proposed in literature
have not been understood well enough. In this paper we therefore investigate the
basic algebraic laws of incremental change computation as well as their direct encoding
in form of deductive rules from a new perspective. In addition we address the problems
arising when the entire process of update propagation is driven by a (semi-)naive fixpoint
procedure applied to the rules encoding the incremental definitions of induced updates
Checking Consistency of Database Constraints
This paper addresses the problem of consistency of a set of
integrity constraints itself, independent from any state. It is
pointed out that database constraints have not only to be
consistent, but in addition to be finitely satisfiable. This
stronger property reflects that the constraints have to admit a
finite set of (stored as well as derivable) facts. As opposed to
consistency, being undecidable, finite satisfiability is semidecidable.
For efficiency purposes we investigate methods that
check both finite satisfiability as well as unsatisfiability . Two
different methods are proposed which extend two alternative
approaches to refutation
Sur la Validité des Schémas de Bases de Données
Les mises a jour (Tun schema de base de donnees peuvent porter sur ses trois Constituante, ( l ) les
declarations de structures, (2) les regies de coherence (et de deduction) et (3) les transactions. Ces
Constituante doivent verifier certaines proprietes, definissant les Schemas valides. Un Systeme de
gestion de Schemas doit pouvoir verifier la validite des sche"mas (independamment de toute extension
de la base) et detecter les modifications des Schemas violant les conditions de validite. Dans cet
article nous decrivons tout d'abord Papproche que nous avons suivi pour realiser un Systeme de
gestion des declarations de structures, premier composant disponible d'un Systeme de gestion de
Schemas en cours de developpement. Cette approche fait de la validite de declarations de structures
un probleme semblable a la verification des regies de coherence dans une base de donnees. Nous
montrons ensuite que la validite des regies (de coherence et de deduction) correspond a une propriete
logique plus forte que la consistence, la satisfaisabilite finie. Dans certains cas, cette propriete peut
elre detected par des methodes de refutation de preuve automatique de theoremes. Considerant la
resolution, sur laquelle s'appuient les procedures de refutation les plus performantes, nous
caracterisons les additions necessaires pour etendre une procedure de refutation en une methode
complete pour la satisfaisabilite finie. Une telle extension de la resolution est decrite
Update propagation in chimera, an active DOOD language
Propagating updates is an important task to be performed within many database
services such as integrity checking, maintenance of materialized views, and condition
monitoring. This paper is concerned with the propagation of updates in an active DOOD
language. The approach proposed is to make use of Chimera triggers for computing
induced updates. It will be shown how a subset of Chimera's deductive rules can be
compiled to update propagation triggers. In its expressiveness the rule set considered
corresponds to that of Datalog with sets and negation. Using triggers for implementing
update propgation has the advantage that no special component has to be implemented
as a trigger mechanism has. to exist anyway. In this paper we will not propose new
techniques for computing induced updates but will transfer the techniques - well-known
for the relational model - to the object-oriented case
- …