Yanjing Wang
Department of Philosophy Peking University
ICLA
Publication Types:
Knowable as Knowing How to Inquire
Arbitrary Public Announcement Logic (APAL) and its variants are proposed to formalize knowability dynamically based on public announcements as the means to update knowledge. In this paper, we introduce yet another variant HAPAL of APAL, which is based on questions instead of announcements, and captures knowability as knowing how to know by asking questions. Therefore, the prime modality in our language can also be viewed as a know-how operator sharing the same ∃□ bundled structure as logics of knowing how in the literature. This change in the semantics of the
arbitrary announcement operator results in a highly non-trivial logic, which departs from the existing versions of APAL. As we will show, it is already strictly more expressive than APAL and epistemic logic on S5 models in the single-agent case. Moreover, it lacks compactness and Craig interpolation property. We also provide a sound and weakly complete axiomatization.
Knowing values and public inspection
Abstract: We present a basic dynamic epistemic logic of “knowing the value”. Analogous to public announcement in standard DEL, we study “public inspection”, a new dynamic operator which updates the agents’ knowledge about the values of constants.We provide a sound and strongly complete axiomatization for the single and multi-agent case, making use of the well-known Armstrong axioms for dependencies in databases.
Achieving while maintaining: A logic of knowing how with intermediate constraints
Abstract: In this paper, we propose a ternary knowing how operator to express that the agent knows how to achieve $\phi$ given $\psi$ while maintaining $\chi$ in-between. It generalizes the logic of goal-directed knowing how proposed by Wang in [10]. We give a sound and complete axiomatization of this logic.
Representing Imperfect Information of Procedures with Hyper Models
Abstract. When reasoning about knowledge of procedures under imperfect information, the explicit representation of epistemic possibilities blows up the S5-like models of standard epistemic logic. To overcome this drawback, in this paper, we propose a new logical framework based on compact models without epistemic accessibility relations for reasoning about knowledge of procedures. Inspired by the 3-valued abstraction method in model checking, we introduce hyper models which encode the imperfect procedural information. We give a highly non-trivial 2-valued semantics of epistemic dynamic logic on such models while validating all the usual S5 axioms. Our approach is suitable for applications where procedural information is ‘learned’ incrementally, as demonstrated by various examples.
Reasoning about protocol change and knowledge
Abstract. In social interactions, protocols govern our behavior and assign meaning to actions. In this paper, we investigate the dynamics of protocols and their epistemic effects. We develop two logics, inspired by Propositional Dynamic Logic (PDL) and Public Announcement Logic (PAL), for reasoning about protocol change and knowledge updates. We show that these two logics can be translated back to the standard PDL and PAL respectively.