Logic and algebraic languages for interoperability in multidatabase systems

One way of achieving interoperability among heterogeneous, distributed DBMs is through a multidatabase system. Recently, there is an increasing use of CORBA implementation in developing multidatabase systems. Panorama is a multidatabase system that has been implemented on the top of CORBA compliant namely VisiBroker. It aims to achieve interoperability among Oracle, Sybase and other different DMBSs through the registration of these DBMSs to Panorama and through the single global query language-PanoSQL designed for this system. In this paper, we first introduce CORBA for the interoperability in multidatabase systems. Then, a general view for our designed multidatabase system. Panorama, has been given. In section four, we introduce the global query language-PanoSQL designed to achieve interoperability among the different DBMSs implemented in Panorama. Then, as an example, we present the registration of Oracle to panorama in order to achieve interoperability in this system. And, finally, a conclusion and the future work for this system have been given.

Since relational DBMSs are wide-spread, providing a relational global view for users who are only familiar with the relational model to access data in a multidatabase system is significant. However, the prior work on schema integration can not effici

First Order String Calculus (FOSC), introduced in this paper, is a generalization of First Order Predicate Calculus (FOPC). The generalization step consists in treating the unrestricted strings, which may contain variable symbols and a nesting structure, similarly to the predicate symbols in FOPC. As a logic programming technology, FOSC, combined with a string unification algorithm and the resolution principle, eliminates the need to invent logical atoms. An important aspect of the technology is the possibility to apply a matching of the text patterns immediately in logical reasoning. In this way the semantics of a text can be defined by string examples, which only demonstrate the concepts, rather than by a previously formalized mathematical knowledge. The advantages of avoiding this previous formalization are demonstrated. We investigate the knowledge representation aspects, the algorithmic properties, the brain simulation aspects, and the application aspects of FOSC theories in comparison with those of FOPC theories. FOSC is applied as a formal basis of logic programming language Sampletalk, introduced in our earlier publications.

The integration of network data base management and problem resolution

Pegasus is an object-oriented multidatabase system being developed at Hewlett-Packard Laboratories. The goal of the system is to provide facilities for multidatabase applications for accessing and manipulating multiple autonomous heterogeneous object-oriented, relational and other databases. This paper gives an overview of the architecture, describes the common object model and gives the justification for adapting the model for a multidatabase system. It describes the database environment of the system, discusses how to manage schemas consisting of types and functions from multiple databases. It briefly describes the features of the data language and gives an example. It discusses a method for dealing with object identification issues in a multidatabase system, reviews schema integration issues and briefly mentions schema mapping to relational models. >

This paper is concerned with the relationship of the termination problem for programs and abstract programs to the validity of certain formulas in the first-order predicate calculus. By exploiting this relationship, subclasses of abstract programs for which the termination problem is decidable can be isolated. Moreover, known proof procedures for the first-order predicate calculus (e.g. resolution) can be applied to prove the termination of both programs and abstract programs. The correctness and equivalence problems of abstract programs are shown to be reducible to the termination problem.

We present a logic for reasoning about complex objects, which is a revised and significantly extended version of Maier's O-logic [Mai86]. The logic naturally supports complex objects, object identity, deduction, is tolerant to inconsistent data, and has many other interesting features. It elegantly combines the object-oriented and value-oriented paradigms and, in particular, contains all of the predicate calculus as a special case. Our treatment of sets is also noteworthy: it is more general than ELPS [Kup87] and COL [AbG87], yet it avoids the semantic problems encountered in LDL [BNS87]. The proposed logic has a sound and complete resolution-based proof procedure.

A logic for programming with complex objects

The paper starts with an examination and critique of Tarski's well-known proposed explication of the notion of logical operation in the type structure over a given domain of individuals as one which is invariant with respect to arbitrary permutations of the domain. The class of such operations has been characterized by McGee as exactly those definable in the language ${\cal L}_{\infty,\infty}$. Also characterized similarly is a natural generalization of Tarski's thesis, due to Sher, in terms of bijections between domains. My main objections are that on the one hand, the Tarski-Sher thesis thus assimilates logic to mathematics, and on the other hand fails to explain the notion of same logical operation across domains of different sizes. A new notion of homomorphism invariant operation over functional type structures (with domains $M_0$ of individuals and $\{T,F\}$ at their base) is introduced to accomplish the latter. The main result is that an operation is definable from the first-order predicate calculus without equality just in case it is definable from homomorphism invariant monadic operations, where definability in both cases is taken in the sense of the $\lambda$-calculus. The paper concludes with a discussion of the significance of the results described for the views of Tarski and Boolos on logicism.

In this paper it is indicated how the results obtained in [l] may be extended to languages with the syntax of first-order predicate calculus. An additional important result is demonstrated to the effect that there can be no proof procedure for the set of logically contingent expressions. The proof of this latter result depends on the undecidability of the predicate calculus, and hence it does not apply to the sentential calculus. At this time the existence of a proof procedure for the logical contingencies of sentential calculus is an open question.

A simplified problem reduction format

A certain variety of anti-realist thinks of accepted natural science, or significant portions of it, as not literally true, or as in some sense not measuring up to the standards for realism revealed by philosophers. By contrast, the naturalism that Quine so persistently espoused is by its own lights a species of scientific realism. It holds that there is no point of view that stands above science — the various sciences including mathematics and logic — from which one could gainsay or substantially re-interpret large swaths of its findings. It is naturalized epistemology, but also naturalized metaphysics, even if Quine did not call it that.1 Quine is explicit that the very ideas of truth, reference, objectivity and so on have only the sense afforded to them within natural science itself (or rather: regimented natural science — roughly, the most streamlined version of it as represented in the first-order predicate calculus with identity). Realism about the external world, about the past and future, and about induction, to take the most general examples, are by and large assumed by science (and by common sense); there is no other point of view, no higher standard, no further question with respect to such commitments. To be sure, they are factual assumptions that could conceivably be overturned, but are as well-founded as any part of the general naturalistic world view.

In this article we prove a theorem on the definitional embeddability into first-order predicate logic without equality of such well-known mathematical theories as group theory and the theory of Abelian groups. This result may seem surprising, since it is generally believed that these theories have a non-logical content. It turns out that the central theory of general algebra are purely logical. Could this be the reason that we find them in many branches of mathematics? This result will be of interest not only for logicians and mathematicians but also for philosophers who study foundations of logic and its relation to mathematics.

A uniform analysis is offered for the source of the locations specified by all references in English to spatial properties including location and movement. This source is argued to be the location of events and states of affairs. These locations are specified by sets showing spaces momentarily occupied. Descriptions of motion are accounted for through a variety of ways of referencing these sets. Some classes of simple clauses are identified as requiring semantic analysis involving multiple events and states of affairs. This importantly allows spatial references to be associated with different events and states of affairs. Identification of object location is accounted for by use of extra inference rules or meaning postulates. A number of other explanations are suggested for more limited and derivative phenomena. The analysis is developed within a Case-like notation presented in the first-order predicate calculus. It is supported by an extensive analysis of spatial reference phenomena and by identification of ancillary benefits.

Metalogical control for logic programs