This study focuses on the question: "What are the computational formalisms at the heart of deceptive and counter-deceptive machines?" We formulate deception using a dynamic epistemic logic. Three different types of deception are considered: deception by lying, deception by bluffing and deception by truth-telling, depending on whether a speaker believes what he/she says or not. Next we consider various situations where an act of deceiving happens. Intentional deception is accompanied by a speaker's intent to deceive. Indirect deception happens when false information is carried over from person to person. Self-deception is an act of deceiving the self. We investigate formal properties of different sorts of deception.

In this abstract, we first consider abduction in human dialogues. Two different types of abduction, objective abduction and subjective abduction, are introduced and formulated using propositional modal logic. We next formulate conversational implicature in the same logic and contrast it with abduction in dialogues. According to our formulation, abduction uses private belief of a reasoner, while conversational implicature relies on common knowledge between participants in conversation. The results characterize how hearers use abduction or conversational implicatures to figure out what speakers have implicated and show how two commonsense inferences are distinguished.

This paper investigates the use of high-level action languages for representing and reasoning about commitments in mulit-agent domains. The paper introduces the language L mt with features motivates by the problem of representing commitments; in particular, it shows how L mt can handle both simple commitment actions and complex commitment protocols. The semantics of L mt provides a uniform solution to different problems in reasoning about commitments, e.g., the problem of (i) verifying whether an agent fails (or succeeds) to deliver on its commitments; (ii) identifying pending commitments; and (iii) suggesting ways to satisfy pending commitments.