S Buvac. Resolving lexical ambiguity using a formal theory of context. In K van Deemter and S Peters, editors, Semantic Ambiguity and Underspecification, pages 101-- 124. CSLI Publications, 1996.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....for preferences based on reasoning about exceptions or for explicit priorities. There are some proposals to use logics for lexical knowledge representation and reasoning. An epistemic logic has been used as the basis of a framework for reasoning about context for resolving lexical ambiguity [Buv96]. Unfortunately, the reasoning is monotonic and so offers no contextdependent default reasoning. A new variant of default logic has been proposed for reasoning about ambiguity according to context [Poe96] However, there is no mechanism for determining context for a given ambiguous word, and the ....

S Buvac. Resolving lexical ambiguity using a formal theory of context. In K van Deemter and S Peters, editors, Semantic Ambiguity and Underspecification, pages 101-- 124. CSLI Publications, 1996.

....1. Conventional linguistic applications like the referents of pronouns can be treated using contexts as objects, but formalized contexts are also useful for more complex anaphora. For example, we need to relate the surgeon s Scalpel to the sentence Please hand me a number 3 scalpel . See [Buv96]. These applications require associating contexts with sentences or parts of sentences. 2. Defining a theory in a narrow context in a way that permits it to be lifted to a richer outer context and applied. McC93] discusses lifting a 3 simple theory of above(x; y) as the transitive closure of ....

Sasa Buvac. Resolving lexical ambiguity using a formal theory of context. In Semantic Ambiguity and Underspecification. CSLI Lecture Notes, Center for Studies in Language and Information, Stanford, CA, 1996. 6

....that is, they made observably false assumptions about the nature of language. For example, Schank s scripts assumed that situations always uniquely pre determine the word meanings and inferences that are applicable in the situation. McCarthy and Buvac s approach seems to be, in effect, Schankian. Buvac [1996], for example, chooses between two homonymous meanings of the word bank in a logical form based on the sentence Vanja is getting money at a bank by assuming that all other words in the sentence are unambiguous and can be used to find the exact right axiom in the commonsense context. As far as I ....

....Cartesian coordinates work quite nicely for the former in simple everyday applications. For the latter, McCarthy and Buvac s [1997] formalization of context simpliciter can, under certain assumptions, find the price of airplane parts and disambiguate two homonymous senses of the word bank [Buvac 1996]. But however useful they are in local human day to day navigation, Cartesian coordinates are not a very useful formalization for what is now known in theoretical physics about the nature of space and time. And simple formalizations of context simpliciter might work on toy examples, but there s no ....

Buvac, Sasa, 1996. "Resolving lexical ambiguity using a formal theory of context." In: van Deemter, Kees and Peters, Stanley, 1996. Semantic ambiguity and underspecification, Stanford, CA: CSLI Publications. 101--124.

....is, they made observably false assumptions about the nature of language. For example, Schank s scripts assumed that situations always uniquely pre determine the word meanings and inferences that are applicable in the situation. McCarthy and Buvac s approach seems to be, in effect, Schankian. Buvac (1996), for example, chooses between two homonymous meanings of the word bank in a logical form based on the sentence Vanja is getting money at a bank by assuming that all other words in the sentence are unambiguous and can be used to find the exact right axiom in the commonsense context. As far as I ....

....Cartesian coordinates work quite nicely for the former in simple everyday applications. For the latter, McCarthy and Buvac s (1997) formalization of context simpliciter can, under certain assumptions, find the price of airplane parts and disambiguate two homonymous senses of the word bank (Buvac 1996). But however useful they are in local human day to day navigation, Cartesian coordinates are not a very useful formalization for what is now known about the nature of space and time in theoretical physics. And simple formalizations of context simpliciter might work on toy examples, but there s no ....

Buvac, Sasa (1996). "Resolving lexical ambiguity using a formal theory of context." In: van Deemter, Kees and Peters, Stanley (1996). Semantic ambiguity and underspecification, Stanford, CA: CSLI Publications. 101--124.

....This knowledge would have to be used in inference, which will be all the more difficult because it is defeasible. For example, the information about how much weight boys can carry is suspendible in fairy tales) Presumably, the disambiguating inference would go along the following lines (cf. Buvac 1996), where cs represents common sense knowledge, that is, the knowledge shared by all competent speakers of the language. A grammatically possible interpretation is one that is in accordance with all the linguistic rules governing the sentence uttered (including the rules governing discourse ....

....flight can be operated by Quantas and American Airlines at the same time, so under this interpretation, the query contains an inconsistency. Let us assume that the interpretation of the query resulting from the interpretation American 5 can be refuted on the basis of this inconsistency. See e.g. Buvac 1996. The result of this disambiguation step is a second, more specific representation, kfxfflf lights : American 1 jAmerican 2 (x) Operator(x) Quantasgk, This representation happens to be specific enough to warrant an answer. Intuitively, this 16 is because both remaining interpretations of ....

Buvac, S. (1996), `Resolving Lexical Ambiguity using a Formal Theory of Context', in Van Deemter and Peters (Eds.) Semantic Ambiguity and Underspecification, CSLI Publications, Stanford 1996.

....of applications for DATR see [EG95] for Laurel see [BCP94] and for PDU see [LBAC95] There are some proposals to use logics for lexical knoweldge representation and reasoning. An epistemic logic has been used as the basis of a framework for reasoning about context for resolving lexical ambiguity [Buv96]. Unfortunately, the reasoning is monotonic and so offers no contextdependent default reasoning. A new variant of default logic has been proposed for reasoning about ambiguity according to context [Poe96] However, there is no mechanism for determining context for a given ambiguous word, and the ....

S Buvac. Resolving lexical ambiguity using a formal theory of context. In K van Deemter and S Peters, editors, Semantic Ambiguity and Underspecification, pages 101-- 124. CSLI Publications, 1996.

....ffl Resolving lexical ambiguity: By using context, the task of choosing the right interpretation of lexical ambiguity is made easier. 12 However, there are arguments that while a context formalism can represent lexical ambiguity, additional knowledge is needed to perform the resolution [15]. ffl Flexible entailment: Context might effect the entailment relation. For example, in a particular context, entailment might warrant a closed world assump 9 We will see that in McCarthy s newer work [45] holds(p; c) is renamed ist(c;p) 10 This is desirable because [f]ormalizing ....

S. Buvac. Resolving lexical ambiguity using a formal theory of context. In K. van Deemter and S. Peters, editors, Semantic Ambiguity and Underspecification, number 55 in CSLI Lecture Notes. Center for the Study of Language and Information, Stanford, CA, 1996.

.... ( Mug92] to generate default rules for a domain; 3) Using co locational data for knowledge engineering; and (4) Using machine readable dictionaries and thesauri for knowledge engineering [Mei93] The Lexica framework is complementary to formalizations of the notion of aboutness such as [BH94,Buv95,Hun96] A Lexica knowledgebase could potentially be used in such frameworks to allow identification of, and reasoning with, relations such as article A is about topic T . Finally, we can consider the Lexica approach as a move towards reusable knowledgebases or general knowledge systems. CYC is ....

S Buvac. Resolving lexical ambiguity using a formal theory of context. In K van Deemter and S Peters, editors, Semantic Ambiguity and Underspecification, pages 101--124. CSLI Publications, 1995.

.... pianos (What is their shape and weight ) Let us assume that all this information may once be formally represented in some common sense knowledge base, perhaps of the kind advocated in Guha and Lenat 1990. This knowledge would have to be used in inference, along the following lines (see e.g. Buvac 1996), where cs represents the knowledge presumably shared by all competent speakers of the language. A grammatically possible interpretation is an interpretation that is logically well formed. 1 as well as in accordance with all the linguistic rules governing the sentence as uttered in its ....

....flight can be operated by Quantas and American Airlines at the same time, so under this interpretation, the query contains an inconsistency. Let us assume that the interpretation of the query resulting from the interpretation AMERICAN 5 can be refuted on the basis of this inconsistency. See e.g. Buvac 1996. The result of this disambiguation step is a second, more specific representation, kfxfflf lights : American 1 jAmerican 2 (x) Operator(x) Quantasgk, This representation happens to be specific enough to warrant an answer. Intuitively, this is because both remaining interpretations of the ....

Buvac, S. (1996), `Resolving Lexical Ambiguity using a Formal Theory of Context', in Van Deemter and Peters (Eds.) Semantic Ambiguity and Underspecification, CSLI Publications, Stanford 1996.

....motivate the use of contexts as formal mathematical objects in AI. 1. Conventional linguistic applications like the referents of pronouns and anaphora are readily treated by contexts. For example, we need to relate the surgeon s Scalpel to the sentence Please hand me a number 3 scalpel , cf. (Buvac 1996). 2. Defining a theory in a way that permits it to be lifted from a narrow context to a richer outer context. McCarthy 1993) discusses lifting a simple theory of above(x; y) as the transitive closure of on(x; y) to an outer situation calculus context that uses on(x; y; s) and above(x; y; s) A ....

Buvac, S. 1996. Resolving lexical ambiguity using a formal theory of context. In van Deemter, K., and Peters, S., eds., Semantic Ambiguity and Underspecification. CSLI Lecture Notes. To appear.

....for various extensions of the general systems, we show that our propositional logic is decidable, and give a comparison to Kripke s possible worlds semantics. We also discuss some extensions and applications of our logics. Many of the results of this thesis have been previously published in [49, 19, 12, 11, 15, 14, 18]. See also [16] 1.1 Notation We use standard mathematical notation. If X and Y are sets, then X p Y is the set of partial functions from X to Y . P(X) is the set of subsets of X. X is the set of all finite sequences, and we let x = x 1 ; x n ] range over X . ffl is the empty ....

Sasa Buvac. Resolving lexical ambiguity using a formal theory of context. In Kees Van Deemter and Stanley Peters, editors, Semantic Ambiguity and Underspecification. CSLI Publications, 1996. Distributed by Cambridge University Press: CSLI Lecture Notes Number 55.

No context found.

S Buvac. Resolving lexical ambiguity using a formal theory of context. In K van Deemter and S Peters, editors, Semantic Ambiguity and Underspecification, pages 101-- 124. CSLI Publications, 1996.

No context found.

Buvac, Sasa. 1996b. Resolving lexical ambiguity using a formal theory of context.

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