New Directions in Model Checking Dynamic Epistemic Logic

Dynamic Epistemic Logic (DEL) can model complex information scenarios in a way that appeals to logicians. However, its existing implementations are based on explicit model checking which can only deal with small models, so we do not know how DEL performs for larger and real-world problems. For temporal logics, in contrast, symbolic model checking has been developed and successfully applied, for example in protocol and hardware verification. Symbolic model checkers for temporal logics are very efficient and can deal with very large models. In this thesis we build a bridge: new faithful representations of DEL models as so-called knowledge and belief structures that allow for symbolic model checking. For complex epistemic and factual change we introduce transformers, a symbolic replacement for action models. Besides a detailed explanation of the theory, we present SMCDEL: a Haskell implementation of symbolic model checking for DEL using Binary Decision Diagrams. Our new methods can solve well-known benchmark problems in epistemic scenarios much faster than existing methods for DEL. We also compare its performance to to existing model checkers for temporal logics and show that DEL can compete with established frameworks. We zoom in on two specific variants of DEL for concrete applications. First, we introduce Public Inspection Logic, a new framework for the knowledge of variables and its dynamics. Second, we study the dynamic gossip problem and how it can be analyzed with epistemic logic. We show that existing gossip protocols can be improved, but that no perfect strengthening of "Learn New Secrets" exists

Directional adposition use in English, Swedish and Finnish

Directional adpositions such as to the left of describe where a Figure is in relation to a Ground. English and Swedish directional adpositions refer to the location of a Figure in relation to a Ground, whether both are static or in motion. In contrast, the Finnish directional adpositions edellä (in front of) and jäljessä (behind) solely describe the location of a moving Figure in relation to a moving Ground (Nikanne, 2003). When using directional adpositions, a frame of reference must be assumed for interpreting the meaning of directional adpositions. For example, the meaning of to the left of in English can be based on a relative (speaker or listener based) reference frame or an intrinsic (object based) reference frame (Levinson, 1996). When a Figure and a Ground are both in motion, it is possible for a Figure to be described as being behind or in front of the Ground, even if neither have intrinsic features. As shown by Walker (in preparation), there are good reasons to assume that in the latter case a motion based reference frame is involved. This means that if Finnish speakers would use edellä (in front of) and jäljessä (behind) more frequently in situations where both the Figure and Ground are in motion, a difference in reference frame use between Finnish on one hand and English and Swedish on the other could be expected. We asked native English, Swedish and Finnish speakers’ to select adpositions from a language specific list to describe the location of a Figure relative to a Ground when both were shown to be moving on a computer screen. We were interested in any differences between Finnish, English and Swedish speakers. All languages showed a predominant use of directional spatial adpositions referring to the lexical concepts TO THE LEFT OF, TO THE RIGHT OF, ABOVE and BELOW. There were no differences between the languages in directional adpositions use or reference frame use, including reference frame use based on motion. We conclude that despite differences in the grammars of the languages involved, and potential differences in reference frame system use, the three languages investigated encode Figure location in relation to Ground location in a similar way when both are in motion. Levinson, S. C. (1996). Frames of reference and Molyneux’s question: Crosslingiuistic evidence. In P. Bloom, M.A. Peterson, L. Nadel & M.F. Garrett (Eds.) Language and Space (pp.109-170). Massachusetts: MIT Press. Nikanne, U. (2003). How Finnish postpositions see the axis system. In E. van der Zee & J. Slack (Eds.), Representing direction in language and space. Oxford, UK: Oxford University Press. Walker, C. (in preparation). Motion encoding in language, the use of spatial locatives in a motion context. Unpublished doctoral dissertation, University of Lincoln, Lincoln. United Kingdo

A simple account of multiagent epistemic planning

International audienceA realistic model of multiagent planning must allow us to model notions which are absent in classical planning such as communication and knowledge. We investigate multiagent planning based on a simple logic of action and knowledge that is based on the visibility of propositional variables. Using such a formal logic allows us to deduce the validity of a plan from the validity of the individual actions which compose it. We present a coding of multiagent planning problems expressed in this logic into the classical planning language PDDL. Feeding the resulting problem into a PDDL planner provides a provably correct plan for the original multiagent planning problem. We use the gossip problem as a running example

Epistemic protocols for dynamic gossip

A gossip protocol is a procedure for spreading secrets among a group of agents, using a connection graph. In each call between a pair of connected agents, the two agents share all the secrets they have learnt. In dynamic gossip problems, dynamic connection graphs are enabled by permitting agents to spread as well the telephone numbers of other agents they know. This paper characterizes different distributed epistemic protocols in terms of the (largest) class of graphs where each protocol is successful, i.e. where the protocol necessarily ends up with all agents knowing all secrets

Let's Get Organised: Practicing and Valuing Scientific Work Inside and Outside the Laboratory

Over the past thirty years there has been a significant turn towards practice and away from institutions in sociological frameworks for understanding science. This new emphasis on studying \'science in action\' (Latour 1987) and \'epistemic cultures\' (Knorr Cetina 1999) has not been shared by academic and policy literatures on the problem of women and science, which have focused on the marginalisation and under-representation of women in science careers and academic institutions. In this paper we draw on elements of both these approaches to think about epistemic communities as simultaneously practical and organisational. We argue that an understanding of organisational structures is missing in science studies, and that studies of the under-representation of women lack attention to the detail of how scientific work is done in practice. Both are necessary to understand the gendering of science work. Our arguments are based on findings of a qualitative study of bioscience researchers in a British university. Conducted as part of a European project on knowledge production, institutions and gender the UK study involved interviews, focus groups and participant observation in two laboratories. Drawing on extracts from our data we look first at laboratories as relatively unhierarchical communities of practice. We go on to show the ways in which institutional forces, particularly contractual insecurity and the linear career, work to reproduce patterns of gendered inequality. Finally, we analyse how these patterns shape the gendered value and performance of \'housekeeping work\' in the laboratory.Women, Science, Laboratory, Epistemic Community, Organisation, Value, Work, Career, Housekeeping

To Be Announced

In this survey we review dynamic epistemic logics with modalities for quantification over information change. Of such logics we present complete axiomatizations, focussing on axioms involving the interaction between knowledge and such quantifiers, we report on their relative expressivity, on decidability and on the complexity of model checking and satisfiability, and on applications. We focus on open problems and new directions for research

Psychiatry, Sex, and Science: The Making of "Adolescent" Motherhood in Southern Brazil.

Research linking teen motherhood to psychoneurodevelopmental causes and pathologies has proliferated in the past two decades. In Brazil, a psychodevelopmental project of teen motherhood has gained traction despite many experts' long-standing commitment to psychodynamic psychiatry and social epidemiology, generating epistemic tension rather than substitution. Drawing on historical ethnography conducted in Southern Brazil, I explore how this project materialized through the co-production of epistemic struggles, remedial interventions, and ontological politics. In showing how this co-production became interwoven with incremental changes in young women's emotions, sexualities, relationships, and bodies, I describe how one particular "kind" of teen motherhood emerged and became entangled with both psychiatric knowledge-production and the angst of working-class political agency. In giving women a contested psychiatric language with which to rework their social-moral worlds, I argue that science did more than conceptualize teen childbearing in pathological terms; it contributed to its troubled transformation