tailieunhanh - Báo cáo khoa học: "REPRESENTING KNOWLEDGE ABOUT KNOWLEDGE AND MUTUAL KNOWLEDGE"

In order to represent speech acts, in a multi-agent context, we choose a knowledge representation based on the modal logic of knowledge KT4 which is defined by Sato. Such a formalism allows us to reason about knowledge and represent knowledge about knowledge, the notions of truth value and of definite reference. | REPRESENTING KNOWLEDGE ABOUT KNOWLEDGE AND MUTUAL KNOWLEDGE Said Soulhi Equipe de Comprehension du Raisonnement Naturel LSI - UPS 118 route de Narbonne 31062 Toulouse - FRANCE ABSTRACT In order to represent speech acts in a multi-agent context we choose a knowledge representation based on the modal logic of knowledge KT4 which is defined by Sato. Such a formalism allows US to reason about knowledge and represent knowledge about knowledge the notions of truth value and of definite reference. I INTRODUCTION Speech act representation and the language planning require that the system can reason about intensional concepts like knowledge and belief. A problem resolver must understand the concept of knowledge and know for example what knowledge it needs to achieve specific goals. Our assumption is that a theory of language is part of a theory of action Austin 14 . Reasoning about knowledge encounters the problem of intensionality. One aspect of this problem is the indirect reference introduced by Frege 7 during the last century. Me earthy ỊÌ5J presents this problem by giving the following example Let the two phrases Pat knows Mike s telephone number 1 and Pat dialled Mike s telephone number 2 The meaning of the proposition Mike s telephone number in 1 is the concept of the telephone number whereas its meaning in 2 is the number itself. Then if we have Mary s telephone number Mike s telephone number we can deduce that Pat dialled Mary s telephone number but we cannot deduce that Pat knows Mary s telephone number because Pat may not have known the equality mentioned above. Thus there are verbs like to know to believe and to want that create an opaque context. For Frege a sentence is a name refe rence of a sentence is its truth value the sense of a sentence is the proposition. In an oblique context the reference becomes the proposition. For example the referent of the sentence p in the indirect context A knows that p is a proposition and no longer a truth value. Me Carthy 15