•  479
    Resolution Spaces: A Topological Approach to Similarity
    In DEXA 2000, Ieee Computer Society. pp. 553-557. 2000.
    A central concept for information retrieval is that of similarity. Although an information retrieval system is expected to return a set of documents most relevant to the query word(s), it is often described as returning a set of documents most similar to the query. The authors argue that in order to reason with similarity we need to model the concept of discriminating power. They offer a simple topological notion called resolution space that provides a rich mathematical framework for reasoning w…Read more
  •  341
    Conditioning by Minimizing Accessibility
    In Giacomo Bonanno, Benedikt Löwe & Wiebe Hoek (eds.), Logic and the Foundations of Game and Decision Theory €“ Loft 8, Springer Berlin Heidelberg. pp. 20-33. 2010.
    This paper presents an axiomatization of a class of set-theoretic conditional operators using minimization of the geodesic distance defined as the shortest path generated by the accessibility relation on a frame. The objective of this modeling is to define conditioning based on a notion of similarity generated by degrees of indistinguishability.
  •  261
    Modal Logics for Topological Spaces
    Dissertation, City University of New York. 1993.
    In this thesis we present two logical systems, $\bf MP$ and $\MP$, for the purpose of reasoning about knowledge and effort. These logical systems will be interpreted in a spatial context and therefore, the abstract concepts of knowledge and effort will be defined by concrete mathematical concepts.
  •  248
    Updating knowledge using subsets
    Journal of Applied Non-Classical Logics 21 (3-4): 427-441. 2011.
    Larry Moss and Rohit Parikh used subset semantics to characterize a family of logics for reasoning about knowledge. An important feature of their framework is that subsets always decrease based on the assumption that knowledge always increases. We drop this assumption and modify the semantics to account for logics of knowledge that handle arbitrary changes, that is, changes that do not necessarily result in knowledge increase, such as the update of our knowledge due to an action. We present a sy…Read more
  •  113
    Knowledge on treelike spaces
    Studia Logica 59 (2): 271-301. 1997.
    This paper presents a bimodal logic for reasoning about knowledge during knowledge acquisitions. One of the modalities represents (effort during) non-deterministic time and the other represents knowledge. The semantics of this logic are tree-like spaces which are a generalization of semantics used for modeling branching time and historical necessity. A finite system of axiom schemes is shown to be canonically complete for the formentioned spaces. A characterization of the satisfaction relation i…Read more
  •  77
    Ordering-based Representations of Rational Inference
    In Jose Julio Alferes, Luis Moniz Pereira & Ewa Orlowska (eds.), JELIA 96, Springer. pp. 176-191. 1996.
    Rational inference relations were introduced by Lehmann and Magidor as the ideal systems for drawing conclusions from a conditional base. However, there has been no simple characterization of these relations, other than its original representation by preferential models. In this paper, we shall characterize them with a class of total preorders of formulas by improving and extending G ̈ardenfors and Makinson’s results f or expectation inference relations. A second representation is application-or…Read more
  •  71
    Relevance Sensitive Non-Monotonic Inference on Belief Sequences
    Journal of Applied Non-Classical Logics 11 (1): 131-150. 2001.
    We present a method for relevance sensitive non-monotonic inference from belief sequences which incorporates insights pertaining to prioritized inference and relevance sensitive, inconsistency tolerant belief revision. Our model uses a finite, logically open sequence of propositional formulas as a representation for beliefs and defines a notion of inference from maxiconsistent subsets of formulas guided by two orderings: a temporal sequencing and an ordering based on relevance relations between …Read more
  •  43
    Geodesic merging
    Synthese 195 (10): 4243-4264. 2018.
    We pursue an account of merging through the use of geodesic semantics, the semantics based on the length of the shortest path on a graph. This approach has been fruitful in other areas of belief change such as revision and update. To this end, we introduce three binary merging operators of propositions defined on the graph of their valuations and we characterize them with a finite set of postulates.
  •  26
    To Preference via Entrenchment
    Annals of Pure and Applied Logic 96 (1--3): 141--155. 1999.
    We introduce a simple generalization of Gardenfors and Makinson’s epistemic entrenchment called partial entrenchment. We show that preferential inference can be generated as the sceptical counterpart of an inference mechanism defined directly on partial entrenchment.
  •  21
    Belief Update Using Graphs
    In David Wilson & Chad H. Lane (eds.), FLAIRS 21, Aaai Press. pp. 649-654. 2008.
    The purpose of this paper is to introduce a form of update based on the minimization of the geodesic distance on a graph. We provide a characterization of this class using set- theoretic operators and show that such operators bijectively correspond to geodesic metrics. As distance is generated by distinguishability, our framework is appropriate in contexts where distance is generated by threshold, and therefore, when measurement is erroneous
  •  20
    Iterated Contraction Based on Indistinguishability
    In Sergei Artemov & Anil Nerode (eds.), LFCS 2013, Springer. 2013.
    We introduce a class of set-theoretic operators on a tolerance space that models the process of minimal belief contraction, and therefore a natural process of iterated contraction can be defined. We characterize the class of contraction operators and study the properties of the associated iterated belief contraction.
  •  18
    Graph-Based Belief Merging
    In van der Hoek Wiebe, Holliday Wesley H. & Wang Wen-Fang (eds.), Logic, Rationality, and Interaction, Springer-verlag. pp. 101-115. 2016.
    Graphs are employed to define a variety of distance-based binary merging operators. We provide logical characterization results for each class of merging operators introduced and discuss the extension of this approach to the merging of sequences and multisets.
  •  18
    Geodesic Revision
    Journal of Logic and Computation 19 (3): 447-459. 2009.
    The purpose of this article is to introduce a class of distance-based iterated revision operators generated by minimizing the geodesic distance on a graph. Such operators correspond bijectively to metrics and have a simple finite presentation. As distance is generated by distinguishability, our framework is appropriate for modelling contexts where distance is generated by threshold, and therefore, when measurement is erroneous.
  •  17
    On Indistinguishability and Prototypes
    Logic Journal of the IGPL 11 (5): 531-545. 2003.
    Tolerance spaces are sets equipped with a reflexive, symmetric, but not necessarily transitive, relation of indistinguishability, and are useful for describing vagueness based on error-prone measurements. We show that any tolerance space can be embedded in one generated by comparisons using prototypical objects. As a result propositions, definable on a tolerance space can be translated into propositions behaving classically.
  •  16
    Entrenchment Relations: A Uniform Approach to Nonmonotonic Inference
    In D. Gabbay, R. Kruse, A. Nonnengart & H. J. Ohlbach (eds.), ESCQARU/FAPR 97, Springer. pp. 282--297. 1997.
    We show that Gabbay’s nonmonotonic consequence relations c an be reduced to a new family of relations, called entrenchment relations. Entrenchment relations provide a direct generalization of epistemic entrenchment and expectation ordering introduced by G ̈ardenfors and Makinson for the study of belief revision and expectation inference, respectively.
  •  8
    Knowledge Theoretic Properties of Topological Spaces
    In Masuch, Michael & Polos Laszlo (eds.), Knowledge Representation and Uncertainty, Springer Verlag. pp. 147--159. 1994.
    We study the topological models of a logic of knowledge for topological reasoning, introduced by Larry Moss and Rohit Parikh (1992). Among our results is the confirmation of a conjecture by Moss and Parikh, as well as the finite satisfiability property and decidability for the theory of topological models.
  •  6
    Preface
    with Melvin Fitting and R. Ramanujam
    Annals of Pure and Applied Logic 96 (1-3): 1. 1999.
    Preface of Festschrift on the occasion of Professor Rohit Parikh's 60th birthday
  • Epistemic Conditionals and the Logic of Subsets
    In Ramaswamy Ramanujam, Lawrence Moss & Can Başkent (eds.), Rohit Parikh on Logic, Language and Society, Springer Verlag. 2017.
    This paper proposes a formalization of conditional reasoning using Moss and Parikh’s logic of subsets so that a reasoner can express both conditional assertions about beliefs, as well as beliefs about conditional assertions. We present a complete axiomatization of the logic and show that it is decidable. A version of the Ramsey test is found to be compatible with this logic and provides a correspondence between conditionals and belief contraction.