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Reviewer: Claudio Delrieux

The knowledge representation and reasoning (KR&R) problem about actions and change is discussed. The book's primary purpose is to provide novel research results on the topic. There are a number of logics for reasoning about actions and change. The purpose of this book is to provide a framework in which existing and new logics can be characterized. More than a mere assembly of test examples to check out several approaches that have been proposed, the book has a more ambitious goal: to assess various reasoning systems. Chapter 1, “Inert and Inhabited Dynamical Systems,” presents a general description of the subject, with its ontological assumptions. The structure of an inhabited dynamical system (IDS) is defined as one or more agents that interact with a reality. An agent, in turn, can be viewed as a material vehicle and an ego or knowledge-level description. A game is a set of moves, that is, actions that the agents perform on reality. A scenario for an IDS is a set of games. The definitions above allow a recasting of some benchmark problems in KR&R (the Yale shooting problem, for instance) in a common setting. This is introduced in chapter 2, “Inference Operations on Scenario Descriptions.” A point presented in this chapter is that logics for reasoning in world descriptions are essentially logics with implicit epistemological assumptions. The assumptions are introduced via designators. The next chapter focuses on the underlying semantics of IDS worlds, basically a partial (transition-state) model semantics or a functional (trajectory) semantics. The range of chronicles in which the set of selected models according to the entailment relation coincides with the set of intended models is an assessment for the entailment relation. Now the author can introduce an elementary feature logic, with its grammar, domains, syntax, and semantics. This is a first step toward the logic for expressing statements about scenario descriptions. Metalogical concepts and notations are also introduced. In chapter 5, “Lexical-domain Object-feature Logic,” the elementary logic of the preceding chapter is generalized to allow an object domain to be associated with a lexical type in the language. Members of the new domain may appear both in formulas and in the interpretations. Syntax and semantics are extended accordingly. This allows the introduction of denotations, that is, feature expressions with fully evaluated arguments. A reasoned example is presented. The next chapter introduces a discrete-time temporal feature logic. A general definition of a discrete-time structure is introduced. The syntax and semantics of the temporal feature logic use timepoints in the temporal structure as one of its sorts. With this formal apparatus, in chapter 7 some classic examples are recast as chronicle completion problems. A classification of chronicle completion problems is provided in chapter 7, and in chapter 8 the intended models for chronicles are discussed. Now the author is ready to present some of the main results of his work. In chapter 9, the general entailment problem is considered, and some methods applicable within the formal framework of the book are presented. These are based on model preference notions, that is, model selection or minimization of change. The notion of range of applicability for entailment methods is defined. Some possible improvements are discussed. In the next chapter, the knowledge representation features of the formalization are enhanced with duration constraints. The author avoids equidurationality using a preference method of chronological assignment of valuations. The final chapters discuss some other representational and formal issues, such as the representation and entailment of composite actions, and soundness considerations. The layout and typesetting of the book are adequate, but the notation tends to be quite heavy (the notation index is nine pages long). A summary is provided at the end of each chapter. Those working in nonmonotonic reasoning, planning, temporal logic, reasoning about actions and change, and related areas will find this book worth reading.