F. Sadri – författare

Logic and object-orientation have come to be recognized as being among the most powerful paradigms for modeling information systems. The term "information systems" is used here in a very general context to denote database systems, software development systems, knowledge­ base systems, proof support systems, distributed systems and reactive systems. One of the most vigorously researched topics common to all information systems is "formal modeling". An elegant high-level abstraction applicable to both application domain and system domain concepts will always lead to a system design from "outside in"; that is, the aggregation of ideas is around real-life objects about which the system is to be designed. Formal methods \yhen applied with this view in mind, especially during early stages of system development, can lead to a formal reasoning on the intended properties, thus revealing system flaws that might otherwise be discovered much later. Logic in different styles and semantics is being used to model databases and their transactions; it is also used to specify concurrent, distributed, real-time, and reactive systems. ,The notion of "object" is central to the modeling of object­ oriented databases, as well as object-oriented design and programs in software engineering. Both database and software engineering communities have undoubtedly made important contributions to formalisms based on logic and objects. It is worthwhile bringing together the ideas developed by the two communities in isolation, and focusing on integrating their common strengths.

Logic and object-orientation have come to be recognized as being among the most powerful paradigms for modeling information systems. The term "information systems" is used here in a very general context to denote database systems, software development systems, knowledge­ base systems, proof support systems, distributed systems and reactive systems. One of the most vigorously researched topics common to all information systems is "formal modeling". An elegant high-level abstraction applicable to both application domain and system domain concepts will always lead to a system design from "outside in"; that is, the aggregation of ideas is around real-life objects about which the system is to be designed. Formal methods \yhen applied with this view in mind, especially during early stages of system development, can lead to a formal reasoning on the intended properties, thus revealing system flaws that might otherwise be discovered much later. Logic in different styles and semantics is being used to model databases and their transactions; it is also used to specify concurrent, distributed, real-time, and reactive systems. ,The notion of "object" is central to the modeling of object­ oriented databases, as well as object-oriented design and programs in software engineering. Both database and software engineering communities have undoubtedly made important contributions to formalisms based on logic and objects. It is worthwhile bringing together the ideas developed by the two communities in isolation, and focusing on integrating their common strengths.

Alan Robinson This set of essays pays tribute to Bob Kowalski on his 60th birthday, an anniversary which gives his friends and colleagues an excuse to celebrate his career as an original thinker, a charismatic communicator, and a forceful intellectual leader. The logic programming community hereby and herein conveys its respect and thanks to him for his pivotal role in creating and fostering the conceptual paradigm which is its raison d’Œtre. The diversity of interests covered here reflects the variety of Bob’s concerns. Read on. It is an intellectual feast. Before you begin, permit me to send him a brief personal, but public, message: Bob, how right you were, and how wrong I was. I should explain. When Bob arrived in Edinburgh in 1967 resolution was as yet fairly new, having taken several years to become at all widely known. Research groups to investigate various aspects of resolution sprang up at several institutions, the one organized by Bernard Meltzer at Edinburgh University being among the first. For the half-dozen years that Bob was a leading member of Bernard’s group, I was a frequent visitor to it, and I saw a lot of him. We had many discussions about logic, computation, and language.