ILLC-LIRa February 2016

illc-lira@list.uva.nl

1 participants
9 discussions

Next Friday: LIRa session: Chenwei Shi
by LIRa Seminar 28 Feb '16

28 Feb '16

Dear all, On Friday March 4th, we will have a LIRa session with Chenwei Shi. Everyone is cordially invited! Speaker: Chenwei Shi (ILLC) Date and Time: Friday, March 4th 2016, 13:00-14:30 Venue: ILLC Seminar Room F1.15, Science Park 107 Title: Beliefs Supported by Arguments. Abstract. In this talk, I will present the ongoing work (with Sonja Smets) which explores the relation between an agent\'s doxastic attitude and her arguments in support of a given claim. Formally, we build further on Dung\'s argumentation framework in Dung 1995. After introducing a number of notions from abstract argumentation theory, including the attack of an argument, the acceptability of an argument, the conflict-freeness of a set of arguments and its admissibility, I will extend the basic framework of the abstract argumentation theory. This extension allows us to define new concepts, indicating when an argument perfectly defends a given claim P or when an argument only strategically defends a given claim P. The concept of strategic defensibility is then used to link an agent\'s arguments to her doxastic attitude. In order to reason about this interaction, we propose a two-dimensional logic. Moreover, I will talk about some possible directions of developing this logic. (Reference: Dung, P. M. (1995). On the acceptability of arguments and its fundamental role in nonmonotonic reasoning, logic programming and n-person games. Artificial intelligence, 77:321-357) Hope to see you there! The LIRa team

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Today at 13:30: LIRa session with Jan Broersen
by LIRa Seminar 26 Feb '16

26 Feb '16

Dear all, please note: The LIRa session today will start at 13:30, i.e. half an hour later than usual. See https://www.illc.uva.nl/lgc/seminar/ or yesterdays e-mail for title and abstract. Hope to see you there! The LIRa team

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Tomorrow: LIRa session: Jan Broersen
by LIRa Seminar 25 Feb '16

25 Feb '16

Dear all, TOMORROW we will have a LIRa session with Jan Broersen. Everyone is cordially invited! Speaker: Jan Broersen (Universiteit Utrecht) Date and Time: Friday, February 26th 2016, 13:00-14:30 Venue: ILLC Seminar Room F1.15, Science Park 107 Title: Agents Necessitating Effects in Newtonian Time and Space: from Power and Opportunity to Effectivity. Abstract. We extend stit logic by adding a spatial dimension. This enables us to distinguish between powers and opportunities of agents. Powers are agent-specific and do not depend on an agent’s location. Opportunities do depend on locations, and are equal for every agent. The central idea is to define the possibility to see to the truth of a condition in space and time as the combination of the power and the opportunity to do so. The focus on agent-relative powers and space-relative opportunities firmly roots effectivity of an autonomous choice making agent in a space-time picture. Our space-time view will be classical Newtonian, since we assume relativistic phenomena do not play a role in agentive effectivity. We show how our semantics naturally distinguishes between different kinds of histories; histories that reflect real (factual) possibilities and histories that reflect counterfactual possibilities (of a particular hypothetical kind). Furthermore, we discuss how the spatial picture sheds a clear light on conceptual problems for the central stit property of ‘independence of agency’. Hope to see you there! The LIRa team

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This Friday: LIRa session: Jan Broersen
by LIRa Seminar 22 Feb '16

22 Feb '16

Dear all, this Friday we will have a LIRa session with Jan Broersen. (The session had been scheduled earlier but was postponed.) Everyone is cordially invited! Speaker: Jan Broersen (Universiteit Utrecht) Date and Time: Friday, February 26th 2016, 13:00-14:30 Venue: ILLC Seminar Room F1.15, Science Park 107 Title: How to Formalize Knowing How: Practical Knowledge as Knowledge about Action-Goal Hierarchies. Abstract. Practical knowledge is the knowledge involved in ‘knowing-how’. We distinguish between two kinds of practical knowledge: (1) explicit practical knowledge, which we define as knowledge about how abstract action is implemented by more concrete action (that is, knowledge about action-hierarchies, such as employed in for example hierarchical task networks), and (2) implicit practical knowledge, which is the kind of practical knowledge that is often referred to as ‘tacit’ and/or \'non-propositional\'. We show how the two kinds of practical knowledge need to be combined to arrive at a notion of ‘knowing-how’. We propose a stit-logic representation of the first kind of practical knowledge and discuss attempts at providing stit-logic characterizations of the second kind (attempts which might be doomed to fail if implicit practical knowledge is indeed non-propositional). Our formal results concern characterizations of the conditions under which ‘knowledge about what one does’ is ‘upwards closed’ in an action hierarchy that is witness to a case of knowing-how. Hope to see you there! Besides, many other sessions were scheduled today. See the ILLC News for details or look on our website for all upcoming LIRa events: https://www.illc.uva.nl/lgc/seminar/ The LIRa team

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Affiliated event tomorrow: Talk by Bob Coecke
by LIRa Seminar 17 Feb '16

17 Feb '16

Dear all, tomorrow Bob Coecke will give a talk at ILLC and we invite everyone to attend. This week there will be no LIRa session on Friday. Speaker: Bob Coecke (Oxford) Date and Time: Thursday, February 18th 2016, 12:00-14:00 Venue: ILLC Seminar Room F1.15, Science Park 107. Title: In pictures: from quantum foundations to natural language meaning (this talk requires no background in physics, nor in linguistics, nor in fancy math!). Abstract: Earlier work on an entirely diagrammatic formulation of quantum theory, which is soon to appear in the form of a textbook [1], has somewhat surprisingly guided us towards an answer for the following question [2]: how do we produce the meaning of a sentence given that we understand the meaning of its words? This work has practical applications in the area of natural language processing, and the resulting tools have meanwhile outperformed existing methods. References: [1] B. Coecke & A. Kissinger (2016, 900 pages, to appear) Picturing Quantum Processes. A first course on quantum theory and diagrammatic reasoning. Cambridge University Press. [2] B. Coecke, M. Sadrzadeh & S. Clark (2010) Mathematical foundations for a compositional distributional model of meaning. arXiv:1003.4394. Hope to see you there! The LIRa team

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Today! LIRA Session: Rahim Ramezanian
by LIRa Seminar 12 Feb '16

12 Feb '16

Dear all, today we will have a LIRa session with Rahim Ramezanian. Everyone is cordially invited! Speaker: Rahim Ramezanian Date and Time: Friday, February 12th 2015, 13:00 - 14:30. Venue: ILLC Seminar Room F1.15, Science Park 107. Title: Epistemic Protocols for Dynamic Gossip. Abstract. 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 phone numbers of other agents they know. This talk 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. Hope to see you there! The LIRa team

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This Friday: LIRA Session: Rahim Ramezanian
by LIRa Seminar 10 Feb '16

10 Feb '16

Dear all, Please not that the talk by Jan Broersen has been postponed. Instead we will have a LIRa session with Rahim Ramezanian. Everyone is cordially invited! Speaker: Rahim Ramezanian Date and Time: Friday, February 12th 2015, 13:00 - 14:30. Venue: ILLC Seminar Room F1.15, Science Park 107. Title: Epistemic Protocols for Dynamic Gossip. Abstract. 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 phone numbers of other agents they know. This talk 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. Hope to see you there! The LIRa team

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Next Friday: LIRa session with Jan Broersen
by LIRa Seminar 07 Feb '16

07 Feb '16

Dear all, On Friday February 12th, we will have a LIRa session with Jan Broersen. Everyone is cordially invited! Speaker: Jan Broersen (Universiteit Utrecht) Date and Time: Friday, February 12th 2016, 13:00-14:30 Venue: ILLC Seminar Room F1.15, Science Park 107. Title: TBA. Abstract. TBA. Hope to see you there! The LIRa team

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Tomorrow: LIRa session: Fan Yang
by LIRa Seminar 04 Feb '16

04 Feb '16

Dear all, *tomorrow* we will have a LIRa session with Fan Yang. Everyone is cordially invited! Speaker: Fan Yang (TU Delf) Date and Time: Friday, February 5th 2016, 13:00 - 14:30 Venue: *KdVI Seminar Room F3.20*, Science Park 107. Title: Dependence Logic and Arrow’s Theorem. Abstract: Dependence logic [Väänänen 2007] is a new logical formalism that characterizes the notions of “dependence\" and “independence” in social and natural sciences. The logic adopts the so-called team semantics [Hodges 1997]. The basic idea of this new semantics is that properties of dependence and independence cannot be manifested in single assignments, therefore unlike the usual semantics, formulas of dependence logic are evaluated on sets of assignments (called teams). In this talk, we give a brief introduction to dependence logic and its variants (including independence logic [Grädel, Väänänen 2013]). Then, we will use a version of independence logic to formalize Arrow’s Impossibility Theorem, which can be viewed as a theorem highlighting an interesting conflict between dependence and independence. (The second part of the talk is based on a joint work with Eric Pacuit.) Hope to see you there! The LIRa team

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ILLC-LIRa February 2016