J. Barwise. The situation in logic. Number 17 in Lecture Notes. Center for Study of Language and Information, 1988.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... philosophy, and the mind [10] It was first formulated in detail by Jon Barwise and John Perry in 1983 [11] and has matured over the last decade [24] Various versions of the theory have been applied to a number of linguistic issues, resulting in what is commonly known as situation semantics [7, 8, 9, 23, 29, 31, 33, 48]. The latter aims at the construction of a unified and mathematically rigorous theory of meaning, and the application of such a theory to natural languages. Department of Computer Engineering and Information Science, Faculty of Engineering, Bilkent, 06533 Ankara, Turkey. E mail: ftin, ....

....and Information Science, Faculty of Engineering, Bilkent, 06533 Ankara, Turkey. E mail: ftin, akmang bilkent.edu.tr or ftin, akmang trbilun.bitnet. Fax: 90 4 2664126. Mathematical and logical issues that arise within situation theory and situation semantics have been explored in numerous works [8, 9, 11, 23, 24, 31]. In the past, the development of a mathematical situation theory has been held back by a lack of availability of appropriate technical tools. But by now, the theory has assembled its mathematical foundations based on intuitions basically coming from set theory and logic [1, 8, 23, 25] With a ....

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J. Barwise. The Situation in Logic, CSLI Lecture Notes Number 17, Center for the Study of Language and Information, Stanford, Calif., 1989.

.... The problem with each approach separately, as we see it, and in our opinion the reason it has not worked well in practice, is that there is no such thing as generic knowledge or a generic model [3] All knowledge is situated, in a context, for a purpose, or according to a viewpoint [23] 44] [2] [4] Therefore, any mechanism that does not take into account the context and viewpoint cannot succeed except in the small scale. Combining the two methods by itself suffers from the same problem. Our approach to solving the problem addresses this context issue explicitly. Issues with both ....

....most concrete form of reasoning: the elementary units must be defined before we can start mathematical reasoning. This constraint is not present in linguistic reasoning [32] In addition, we want to generalize sets in two other direc tions: we want to allow contextto leak into the descriptions [2] [44] and we want to allow individuals to have different struc tures in different viewpoints. In many cases, the indefinite boundaries of a category are made more precise (though still somewhat indefinite) by specifying the context under which the category is being considered, thereby allowing ....

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Jori Barwise, The Situation in Logic, CSLI Lecture Notes No. 17, Center for the Study of Language and Information, Stanford U. (1989)

....given first order language as geometrical entities and predicates as relations between these entities. The geometrical objects and their relation in space are presented visually. The system is able to automatically check the validity of the first order formulas the students typed in. Hyperproof [Barwise and Etchemendy, 1998] extends Tarski s World by an additional collection of geometrical objects and relations. Moreover, in Hyperproof students can carry out formal proofs in a natural deduction style calculus. In this calculus predicates that are valid with respect to the fixed model can be used as axioms and ....

Barwise, J. and Etchemendy, J. (1998). Hyperproof. Center for the Study of Language and Information (CSLI), Stanford, California.

....induction on the algebra of natural numbers, which essentially states that the algebra of natural numbers has no proper subalgebras . See [Rut96, Sec.13] for a more detailed explanation. The use of coinduction, both as a proof and as a definition method, is by now widespread (see for instance [BM96], which is a recent textbook on nonwellfounded set theory, and [JR97] for an introductory overview) Its application to languages and regular expressions, in Sections 6 and 10, is to the best of our knowledge new. The calculation rules for a derivatives (Section 5) of regular combinations of ....

J. Barwise and L.S. Moss. Vicious Circles, On the Mathematics of Non-wellfounded Phenomena. CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, 1996.

....for the lambda calculus; Len96] on a higher order concurrent language; Jac96a] on behaviour refinement in object oriented programming. The following papers are using non wellfounded sets as the starting point for semantics: Rut92] Acz94] and [FHL94] on processes and non wellfounded sets; [BM96], a recent textbook on non wellfounded sets and circularity; and [MD97] where corecursion is further studied in that context. Other categorical approaches to bisimulation include [Abr91] on a domain for bisimulation; WN95] on categories of transition systems; Pit94] Fio96] and [Pit96] on ....

J. Barwise and L.S. Moss. Vicious Circles, On the Mathematics of Non-wellfounded Phenomena. CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, 1996.

....is important when we cannot have complete knowledge about objects without thinking of them as being embedded in and interacting with some environment. Thus, context dependency must be understood being as inherently related to partial structures, partial information, and perspectival relativity [Barwise 89] In fact, these are what we need to support the reuse of objects in open systems. Because, in open systems, the programmer cannot foresee all the requirements of the environments in which his objects will be (re)used in the future, the programming system must support the embedding of objects ....

Jon Barwise. The Situation in Logic. Center for the Study of Language and Information, 1989.

....well formed formula in the above system. Following Farradane s idea, the index expressions must be able to represent the following form : E i Relation E j where E i and E j are simple or complex descriptors, and Relation is a relation holding between the descriptors. We choose the situation theory [30, 23] as the derivation system s language: Definition 3.1 (The index expression) Let O be a set of objects and R a set of relations. We define recursively the language L(O,R) of index expressions over O and R as the set of all structures hhR,o 1 , o n ; iii that represents the information that ....

J. Barwise. The situation in logic. Number 17 in Lecture Notes. Center for Study of Language and Information, 1988.

....knowledge by incorporating the notions of situations and perspectives. 1 Introduction In modeling complex systems, one is often required to work with multiple representations of some aspects of reality. The notion of situation has been studied in computer science [Barwise and Perry 83, Barwise 89, Cooper et al. 90] as an important concept in capturing the relative representation of knowledge about the world. The importance of such a notion stems from the epistemological assumption that any representation of the world is partial and relative to some perspective that of the observer. In ....

Jon Barwise. The Situation in Logic. Center for the Study of Language and Information, 1989.

.... idea is in the precise spirit of Barwise and Perry s situation semantics which sees valid inference not as a relation between sentences that preserves truth but as a situated activity whose aim is the extraction of information from a situation, information relevant to the person who extracts it [4, 5]. Thus, the key insight of our paper is that design is a situated activity an activity which is carried out by an intelligent agent (designer) in a rich environment that can be utilized in many ways [1, 2] Design programs assist a designer in specifying an artifact , e.g. a house, a machine, ....

J. Barwise, The Situation in Logic, CSLI Lecture Notes 17, Center for the Study of Language and Information, Stanford, Calif. (1989).

....sponsored by NSF Grant IRI 9120851. As we have stated, we want our models to be governed by constraints, which in our setting are thought of as laws which govern the behavior of partial models, but which are in the background. This is an idea taken from situation theory; see Barwise s book [2], but it is very much akin to the notion of constraint in CLP. We encode a constraint theory into the monotonic forcing relation of a Scott information system appropriate for a first order logic semantics. How to accomplish this encoding is not absolutely clear. One possibility is to use a ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

.... to develop a mathematical theory of meaning which aims to clarify and resolve some tough problems in the study of language, information, logic, and philosophy [7] It was introduced by Jon Barwise and John Perry and stimulated great interest [8] The theory matured within the last ten years or so [5, 14, 15, 36, 52, 53] and various versions of it have been applied to a number of linguistic issues [17] resulting in what is commonly known as situation semantics. This was followed by assorted studies on the computational aspects of the theory, which gave birth to a group of computational systems based on situation ....

....programming, but not to situation theory. Accordingly, PROSIT needs to draw a clear distinction between situations and classes. One would be hard pressed to find anything about inheritance, supersituations, and subsituations when one reads the essential documents on situation theory [8, 5, 17]. The only thing that seems related to these concepts is the part of relation which is defined as follows [5, p. 185] A situation s 1 is a part of a situation s 2 (denoted as s 1 s 2 ) just in case every basic state of affairs that is a fact of s 1 is also a fact of s 2 . However if Sit 1 ....

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J. Barwise. The Situation in Logic. Number 17 in CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, CA, 1989.

....World, as it stands, in the next section, in the third we will look at how some of the ideas behind the software described in section two can help with our problem of providing formal, textual descriptions of the look of systems. 4 Figure 2.1 2. Tarski s World Tarski s World, described in Barwise and Etchemendy (1991), was developed to support the teaching of (classical, first order) logic. Some descriptions of other systems with the same aims, as well as Tarski s World, are given in Goldson and Reeves (1994) suffice to say that Tarski s World was one of the best. The author has had the pleasant experience of ....

Barwise, J. and Etchemendy, J. The Language of First-Order Logic. Center for the Study of Language and Information, 1991.

....at how some of the ideas behind the software described in section two can help with our problem of providing formal, textual descriptions of the look of systems. In the fourth and final section we will consider how this work might be taken forward and improved. 2. Tarski s World Tarski s World [Ba], abbreviated to TW in the rest of this paper, was developed to support the teaching of logic. Some descriptions of other systems with the same aims, as well as TW, are given in [Go2] suffice to say that TW was one of the best. The author has had the pleasant experience of using it for teaching ....

Barwise, J., Etchemendy, J. The Language of First-Order Logic, Center for the Study of Language and Information.

....mean Circularity The semantics of SNePS is circular, notwithstanding its acyclic graph representation. The meanings of certain directly connected nodes influence each other. There is support for the general idea of circular semantics in the AI community. In The Situation in Logic, Jon Barwise ([Barwise, 1989, pages 194 198] lists some inherently circular situations to justify his claim that reality is not wellfounded . Here are simplified versions of two of them: Example 7: A man forgets to bring a dish to a potluck dinner in honor of a friend, and admits, This is a very embarassing situation. ....

Jon Barwise. The Situation in Logic. Center for the Study of Language and Information, Leland Stanford Junior University; Stanford, California, 1989.

....at the time, given the lack of model theoretic techniques appropriate for the task at hand. For us, the key to the successful integration of default reasoning and a modal logic for belief has been domain theory. We think that this theory, and the very much philosophically allied situation theory [3], may have a lot to offer to the knowledge representation community. ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

....the collection of conditions that determine which particular groups of argument roles need to be filled in order to produce an infon. If m n, the infon is said to be unsaturated ; if m = n it is saturated . More information on Situation Theory can be found in Barwise and Perry [6] Barwise [4], Barwise and Etchemendy [5] and Devlin [12, 14, 15] the most up to date version of the theory) 3 Oracles as Situations In this paper, we shall mainly deal with the philosophy behind the nature of information and the ways of gathering relevant information, rather than the purely mathematical ....

J. Barwise. The Situation in Logic. Number 17 in CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, CA, 1987.

....Mathematica, is an inappropriate tool for that purpose. The first systematic and extensive research project questioning the ubiquity of first order logic, and in fact formal logic in general for the semantics of natural language, is perhaps Situation Theory, pioneered by Barwise and Perry [3] in the early 80 s. Situation Theory takes the stand that the key issue for (any) logic is first and foremost its informational character, not languages or proof systems. We recognize that stressing the need for an independent basis for nonmonotonic reasoning, which treats partial information as a ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

....married to Mary. Our approach to this problem, and solution in this example, involves defining a first order logic which is sensitive to constraints: laws which govern the behavior of partial models, but which are in the background. This is an idea taken from situation theory; see Barwise s book [4]. In the above case, situations must respect the constraint that spouse is a partial function. To do this technically, we need to cover the basic apparatus of default domain theory. 3 Default domain theory 3.1 Default Structures First we review Scott s [27] idea of information systems, which ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

....information, logic, philosophy, and the mind. The original theory was due to Jon Barwise and John Perry [6] The theory has matured over the last decade [12] and various versions of it have been applied to a number of linguistic issues, resulting in what is commonly known as situation semantics [2, 3, 5, 11, 15, 16, 18, 25]. Situation semantics aims at the construction of a mathematically rigorous theory of meaning, and the application of such a theory to natural language. The mathematical foundations of the theory are based on intuitions basically coming from set theory and logic [1, 3, 11, 12] One of the ....

....[2, 3, 5, 11, 15, 16, 18, 25] Situation semantics aims at the construction of a mathematically rigorous theory of meaning, and the application of such a theory to natural language. The mathematical foundations of the theory are based on intuitions basically coming from set theory and logic [1, 3, 11, 12]. One of the distinguishing characteristics of situation theory vis a vis another influential semantic theory in the logical tradition [13] is that information content is context dependent. While not much work has been done to construct a computational framework based on situation theory, there ....

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J. Barwise. The Situation in Logic, CSLI Lecture Notes Number 17, Center for the Study of Language and Information, Stanford, CA, 1989.

....to show that the notion of disjunctive default can be elegantly captured by the notion of power default. Our formulas are interpreted in partial models called situations. Like relational data bases, situations consist of sets of tuples, which we call infons. The usage is from situation theory [4]. Our starting points are minimal partial models of quantifier free formulas. This restriction on formulas can be relaxed, though not arbitrarily. The idea is that we start with a specific world description, and instantiate it in a minimal model. For example, the formula broken(l) broken(r) ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

....Most researchers probably suspect that real reasoning is semantic. We suggest that instead of thinking about formal proofs, one should consider the more general notion of information, a move suggested by the theory of denotational semantics of programming languages, and also by situation theory [3]. Toward this end, we introduce the concept of default information structures. These extend the notion of Scott s information systems [18] a general framework accounting for semantic information in the monotonic world. Information systems give an exact characterization of Scott domains, which are ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

....flight, but may perhaps be more efficiently represented by a partial model, one which does not settle all issues. We also remark here that the idea to use partial information in studying nonmonotonicity is not new. See the book [15] for many ways to use partial models in this respect. Barwise [3] has more on partial worlds and situations considered model theoretically, including a treatment of nonmonotonic conditionals. 1.2 Nonmonotonic entailment We now focus on the main topic of the paper: the laws that can govern nonmonotonic reasoning. Since Gabbay [5] a considerable amount of work ....

Jon Barwise. The Situation in Logic. 17. Center for Study of Language and Information, Stanford, California, 1989.

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J. Barwise, The Situation in Logic, CSLI Lecture Notes, No. 17, Center for the Study of Language and Information, Stanford University, Stanford, CA, 1989.

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J. Barwise. The situation in logic. Number 17 in Lecture Notes. Center for Study of Language and Information, 1988.

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J. Barwise. The Situation in Logic. Number 17 in CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, CA, 1989.

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J. Barwise and J. Etchemendy. The Language of First-Order Logic. Number 23 in CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, CA, 1990.

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Barwise, Jon; 1989b. The Situation in Logic. Center for the Study of Language and Information, Stanford.

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