Abstract Programming environments have evolved from purely text based to using graphical user interfaces, and now we see a move toward web-based interfaces, such as Jupyter. Web-based interfaces allow for the creation of interactive documents that consist of text and programs, as well as their output. The output can be rendered using web technology as, for example, text, tables, charts, or graphs. This approach is particularly suitable for capturing data analysis workflows and creating interactive educational material. This article describes SWISH, a web front-end for Prolog that consists of a web server implemented in SWI-Prolog and a client web application written in JavaScript. SWISH provides a web server where multiple users can manipulate and run the same material, and it can be adapted to support Prolog extensions. In this article we describe the architecture of SWISH, and describe two case studies of extensions of Prolog, namely Probabilistic Logic Programming and Logic Production System, which have used SWISH to provide tutorial sites.

Abstract In previous work, we proposed a logic-based framework in which computation is the execution of actions in an attempt to make reactive rules of the formif antecedent then consequenttrue in a canonical model of a logic program determined by an initial state, sequence of events, and the resulting sequence of subsequent states. In this model-theoretic semantics, reactive rules are the driving force, and logic programs play only a supporting role. In the canonical model, states, actions, and other events are represented with timestamps. But in the operational semantics (OS), for the sake of efficiency, timestamps are omitted and only the current state is maintained. State transitions are performed reactively by executing actions to make theconsequentsof rules true whenever theantecedentsbecome true. This OS is sound, but incomplete. It cannot make reactive rules true by preventing theirantecedentsfrom becoming true, or by proactively making theirconsequentstrue before theirantecedentsbecome true. In this paper, we characterize the notion of reactive model, and prove that the OS can generate all and only such models. In order to focus on the main issues, we omit the logic programming component of the framework.

We present an extension of Logic Programming (LP) which, in addition to ordinary LP clauses, also includes integrity constraints, explicit representation of disjunction in the bodies of clauses and in goals, and suspension of atoms as in concurrent l

R. A. KOWALSKI; An Undergraduate Degree in Practical Reasoning, Journal of Logic and Computation, Volume 3, Issue 3, 1 June 1993, Pages 227–229, https://doi.org

This paper is a survey and critical overview of recent work on the extension of logic programming to perform abductive reasoning (abductive logic programming). We outline the general framework of abduction and its applications to knowledge assimilation and default reasoning; and we introduce an argumentation-theoretic approach to the use of abduction as an interpretation for negation as failure. We also analyse the links between abduction and the extension of logic programming obtained by adding a form of explicit negation. Finally we discuss the relation between abduction and truth maintenance.

Logic programs represent knowledge in the form of implications A if B1 and … Bn, n ≥ 0 where the conclusion A is an atomic formula and each condition Bi is either an atomic formula or the negation of an atomic formula. Any variables are assumed to be universally quantified, with a scope which is the entire sentence. A negated condition “not Ai” is deemed to hold if the corresponding positive condition Ai can be shown to fail to hold. This interpretation of negative conditions is called negation by failure (NBF) [Cl 78]. It has the characteristic that only the positive “if-half” of a definition needs to be given explicity. The negative “only-if” half is given implicitly by NBF.

Sentences in first-order predicate logic can be usefully interpreted as programs. In this paper the operational and fixpoint semantics of predicate logic programs are defined, and the connections with the proof theory and model theory of logic are investigated. It is concluded that operational semantics is a part of proof theory and that fixpoint semantics is a special case of model-theoretic semantics.

Various deficiencies of resolution systems are investigated and a new theorem-proving system designed to remedy those deficiencms is presented The system is notable for eliminating redundancies present in SL-resolutlon, for incorporating preprocessing procedures, for liberahzing the order in which subgoals can be activated, for incorporating multidirectmnal searches, and for giving immediate access to pairs of clauses which resolve Examples of how the new system copes with the defic2encies of other theorem-proving systems are chosen from the areas of predicate logic programming and language parsing.The paper emphasizes the historical development of the new system, beginning as a supplement to SL-resolution in the form of classificatmn trees and incorporating an analogue of the Waltz algorithm for picture Interpretation The paper ends with a discussion of the opportunities for using look-ahead to guide the search for proofs