Fagin, RonaldOverview
Most widely held works by
Ronald Fagin
Reasoning about knowledge
by Ronald Fagin
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37 editions published between 1988 and 2011 in English and Italian and held by 1,495 WorldCat member libraries worldwide
Theoretical aspects of reasoning about knowledge : proceedings of the fifth conference (TARK 1994) : March 1316, 1994, Pacific Grove, California
by Conference on Theoretical Aspects of Reasoning about Knowledge
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4 editions published in 1994 in English and held by 79 WorldCat member libraries worldwide Interest in the area of Theoretical Aspects of Reasoning About Knowledge has increased significantly since the first conference was held in 1986 in the Asilomar Conference Center in Pacific Grove, California. Since then, the conference has become a regular biennial event. The results of scientists in the field of reasoning about knowledge have contributed to research in a variety of areas including artificial intelligence, economics, linguistics, philosophy and theoretical computer science
Database theory ICDT 2009 : 12th International Conference on Database Theory, Saint Petersburg, March 2325, 2009 : proceedings
by International Conference on Database Theory
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1 edition published in 2009 in English and held by 17 WorldCat member libraries worldwide
An internal semantics for modal logic : preliminary report
by Ronald Fagin
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6 editions published in 1985 in English and held by 15 WorldCat member libraries worldwide
Proceedings of the 12th International Conference on Database Theory
by Ronald Fagin
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1 edition published in 2009 in English and held by 7 WorldCat member libraries worldwide
Incorporating user preferences in multimedia queries
by Ronald Fagin
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Book
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2 editions published in 1996 in English and held by 6 WorldCat member libraries worldwide Abstract: "In a multimedia database system, queries may be fuzzy: thus, the answer to a query such as (Color='red') may not be 0 (false) or 1 (true), but instead a number between 0 and 1. A conjunction, such as (Color='red') ̂(Sound='loud'), is evaluated by first evaluating the individual conjuncts and then combining the answers by some scoring function. Typical scoring functions include the min (the standard scoring function for the conjunction in fuzzy logic) and the average. We address the question of how to permit the user to weight the importance of atomic subformulas. In particular, we give a semantics for permitting nonuniform weights, by giving an explicit formula (that is based on the underlying scoring function). This semantics permits an efficient implementation with a low database access cost in a multimedia database system in important cases of interest."
Allowing users to weight search terms in information retrieval
by Ronald Fagin
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Book
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3 editions published in 1998 in English and held by 6 WorldCat member libraries worldwide Abstract: "We give a principled method for allowing users to assign subjective weights to the importance of search terms, that is, the terms forming a query, in information retrieval systems. For example, our method makes it possible for a user to say that she cares twice as much about the first search term as the second search term, and to obtain a ranked list of results that reflects this preference. Our method is based upon a simple formula derived from any existing 'unweighted' ranking function. A naive application of the weighted formula would require issuing as many distinct queries as there are search terms, thus damaging the response time of the retrieval. We explain here how to 'smoothly' integrate the formula in most retrieval engines, so as not to affect the retrieval performance in terms of response time."
Fuzzy queries in multimedia database systems
by Ronald Fagin
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Book
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2 editions published in 1998 in English and held by 6 WorldCat member libraries worldwide Abstract: "There are essential differences between multimedia databases (which may contain complicated objects, such as images), and traditional databases. These differences lead to interesting new issues, and I particular [sic] cause us to consider types of queries. For example, in a multimedia database it is reasonable and natural to ask for images that are somehow 'similar to' some fixed image. Furthermore, there are different ways of obtaining and accessing information in a multimedia database than information in a a [sic] traditional database. For example, in a multimedia database, it might be reasonable to have a query that asks for, say, the top 10 images that are similar to a fixed image. This is in contrast to a relational database, where the answer to a query is simply a set. In this paper, we survey some new issues that arise for multimedia queries, with a particular focus on recent research by the author, developed in the context of the Garlic system at the IBM Almaden Research Center."
Easier ways to win logical games
by Ronald Fagin
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Book
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1 edition published in 1996 in English and held by 5 WorldCat member libraries worldwide Abstract: "The key tool in proving inexpressibility results in finitemodel theory is EhrenfeuchtFraïssé games. This paper surveys various gametheoretic techniques and tools that lead to simpler proofs of inexpressibility results. The focus is on firstorder logic and monadic NP."
Relaxing the triangle inequality in pattern matching
by Ronald Fagin
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1 edition published in 1996 in English and held by 5 WorldCat member libraries worldwide Abstract: "Any notion of 'closeness' in pattern matching should have the property that if A is close to B, and B is close to C, then A is close to C. Traditionally, this property is attained because of the triangle inequality (d(A, C) [<or =] d(A, B) + d(b, C), where d represents a notion of distance). However, the full power of the triangle inequality is not needed for this property to hold. Instead, a 'relaxed triangle inequality' suffices, of the form d(A, C) [<or =] c(d(A, B) + d(B, C)), where c is a constant that is not too large. In this paper, we show that one of the measures used for distances between shapes in IBM's QBIC ('Query by Image Content') system satisfies a relaxed triangle inequality, although it does not satisfy the triangle inequality."
The closure of monadic NP
by Miklos Ajtai
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3 editions published between 1997 and 1998 in English and held by 5 WorldCat member libraries worldwide Abstract: "It is a wellknown result of Fagin that the complexity class NP coincides with the class of problems expressible in existential secondorder logic ([sigma]1/1), which allows sentences consisting of a string of existential secondorder quantifiers followed by a firstorder formula. Monadic NP is the class of problems expressible in monadic [sigma]1/1, i.e., [sigma]1/1 with the restriction that the secondorder quantifiers are all unary, and hence range only over sets (as opposed to ranging over, say, binary relations). For example, the property of a graph being 3colorable belongs to monadic NP, because 3colorability can be expressed by saying that there exists three sets of vertices such that each vertex is in exactly one of the sets and no two vertices in the same set are connected by an edge. Unfortunately, monadic NP is not a robust class, in that it is not closed under firstorder quantification. We define closed monadic NP to be the closure of monadic NP under firstorder quantification and existential unary secondorder quantification. Thus, closed monadic NP differs from monadic NP in that we allow the possibility of arbitrary interleavings of firstorder quantifiers among the existential unary secondorder quantifiers. We show that closed monadic NP is a natural, rich, and robust subclass of NP. As evidence for its richness, we show that not only is it a proper extension of monadic NP, but that it contains properties not in various other extensions of monadic NP. In particular, we show that closed monadic NP contains an undirected graph property not in the closure of monadic NP under firstorder quantification and Boolean operations. Our lowerbound proofs require a number of new gametheoretic techniques."
Comparing the power of games on graphs
by Ronald Fagin
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Book
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1 edition published in 1996 in English and held by 5 WorldCat member libraries worldwide Abstract: "The descriptive complexity of a problem is the complexity of describing the problem in some logical formalism. Essentially the only known technique for proving separation results in descriptive complexity is to make use of games on graphs played between two players, called the spoiler and the duplicator. There are two types of these games, which differ in the order in which the spoiler and duplicator make various moves. In one of these games, the rules seem to be tilted towards favoring the duplicator. These seemingly more favorable rules make it easier to prove separation results, since separation results are proven by showing that the duplicator has a winning strategy. In this paper, the relationship between these games is investigated. It is shown that in one sense, the two games are equivalent. Specifically, each family of graphs used in one game (the game with the seemingly more favorable rules for the duplicator) to prove a separation result can in principle be used in the other game to prove the same result. This answers an open question of Ajtai and the author from 1989. It is also shown that in another sense, the games are not equivalent, in that there are situations where the spoiler requires strictly more resources to win one game than the other game. This makes formal the informal statement that one game is easier for the duplicator to win."
Combining fuzzy information from multiple systems
by Ronald Fagin
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Book
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1 edition published in 1995 in English and held by 5 WorldCat member libraries worldwide Abstract: "In a traditional database system, the result of a query is a set of values (those values that satisfy the query). In other data servers, such as a system with queries based on image content, or many text retrieval systems, the result of a query is a sorted list. For example, in the case of a system with queries based on image content, the query might ask for objects that are a particular shade of red, and the result of the query would be a sorted list of objects in the database, sorted by how well the color of the object matches that given in the query. A multimedia system must somehow synthesize both types of queries (those whose result is a set, and those whose result is a sorted list) in a consistent manner. In this paper we discuss the solution adopted by Garlic, a multimedia information system being developed at the IBM Almaden Research Center. This solution is based on 'graded' (or 'fuzzy') sets. Issues of efficient query evaluation in a multimedia system are very different from those in a traditional database system. This is because the multimedia system receives answers to subqueries from various subsystems, which can be accessed only in limited ways. For the important class of queries that are conjunctions of atomic queries, (where each atomic query might be evaluated by a different subsystem), the naive algorithm must retrieve a number of elements that is linear in the database size. By contrast, in this paper an algorithm is given such that if the conjuncts are independent, then with arbitrarily high probability, the total number of elements retrieved in evaluating the query is sublinear in the database size (in the case of two conjuncts, it is of the order of the square root of the size of the database). It is also shown that for such queries, the algorithm is optimal. The matching upper and lower bounds are robust, in the sense that they hold under almost any reasonable rule (including the standard min rule of fuzzy logic) for evaluating the conjunction. Finally, we find a query that is provably hard, in the sense that the naive linear algorithm is essentially optimal."
The hierarchical approach to modeling knowledge and common knowledge
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3 editions published in 1999 in English and held by 5 WorldCat member libraries worldwide
Spectra with only unary function symbols
by Arnaud Durand
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2 editions published in 1998 in English and held by 5 WorldCat member libraries worldwide Abstract: "The spectrum of a firstorder sentence is the set of cardinalities of its finite models. This paper is concerned with spectra of sentences over languages that contain only unary function symbols. In particular, it is shown that a set S of natural numbers is the spectrum of a sentence over the language of one unary function symbol precisely if S is an eventually periodic set."
Common knowledge revisited
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1 edition published in 1996 in English and held by 5 WorldCat member libraries worldwide Abstract: "We consider the commonknowledge paradox raised in [HM90]: common knowledge is necessary for coordination, but common knowledge is unattainable in the real world because of temporal imprecision. We discuss two solutions to this paradox: (1) modeling the world with a coarser granularity, and (2) relaxing the requirements for coordination."
The thirtyseventh annual ACM Symposium on Theory of Computing (STOC 2005) : [guest ed.: Ronald Fagin ...]
by Symposium on Theory of Computing
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1 edition published in 2009 in English and held by 4 WorldCat member libraries worldwide
Contributions to the model theory of finite structures
by Ronald Fagin
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2 editions published in 1973 in English and held by 4 WorldCat member libraries worldwide
Comparing the power of monadic NP games
by Ronald Fagin
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Book
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2 editions published in 1994 in English and held by 3 WorldCat member libraries worldwide Abstract: "It is wellknown that the complexity class NP coincides with the class of problems expressible in existential second order logic ([sigma]¹₁). Monadic NP is the class of problems expressible in monadic [sigma]¹₁, i.e., [sigma]¹₁ with the restriction that the second order quantifiers range only over sets (as opposed to ranging over, say, binary relations). The author introduced a type of EhrenfeuchtFraïssé game, called the monadic NP game, to prove that connectivity is not in monadic NP. Later, Ajtai and the author introduced a seemingly more powerful type of monadic NP game to prove that directed reachability is not in monadic NP. In this paper, the relationship between these games is investigated. It is shown that in a strong sense, the games are equivalent. This equivalence implies that the type of graphs used in the newer game to prove that a class is not in monadic NP can in principle be used in the original game to prove the same result. This answers an open question of Ajtai and the author. On the other hand it is shown that in another sense, the newer monadic NP game is more powerful than the original monadic NP game, in that there are situations where one player (the spoiler) requires strictly more colors to win the newer game than the original game)."
Knowledge and implicit knowledge in a distributed environment : preliminary report
by Ronald Fagin
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2 editions published in 1986 in English and held by 3 WorldCat member libraries worldwide more
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Agent (Philosophy) Artificial intelligence Computational complexity Computer science Computer vision Database management Databases Database searching Firstorder logic Fuzzy sets Game theory Graph theory Information retrieval Knowledge, Theory of Knowledge representation (Information theory) Logic, Symbolic and mathematical Modality (Logic) Model theory Multimedia systems Multiple criteria decision making NPcomplete problems Optical data processing Pattern perception Probabilities Reasoning Spectral theory (Mathematics)

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