ILLC-LIRa March 2021

illc-lira@list.uva.nl

1 participants
9 discussions

LIRa Session: Hans van Ditmarsch
by LIRa Seminar 31 Mar '21

31 Mar '21

Dear all, We will have our next LIRa session tomorrow. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find the details of the talk below. Speaker: Hans van Ditmarsch Date and Time: Thursday, April 1st 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Everyone Knows that Everyone Knows: Gossip Protocols for Super Experts. Abstract. A gossip protocol is a procedure for sharing secrets in a network. The basic action in a gossip protocol is a telephone call wherein the calling agents exchange all the secrets they know. An agent who knows all secrets is an expert. The usual termination condition is that all agents are experts. Instead, we explore protocols wherein the termination condition is that all agents know that all agents are experts. We call such agents super experts. Additionally, we model that agents who are super experts do not make and do not answer calls. Such agents are called engaged agents. We also model that such gossip protocols are common knowledge among the agents. We investigate conditions under which protocols terminate, both in the synchronous case, where there is a global clock, and in the asynchronous case, where there is not. We show that a commonly known protocol with engaged agents may terminate faster than the same protocol without engaged agents. This is a joint work Malvin Gattinger and Rahim Ramezanian, available at https://arxiv.org/abs/2011.13203 . Hope to see you there! The LIRa team

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LIRa Session: Hans van Ditmarsch
by LIRa Seminar 26 Mar '21

26 Mar '21

Dear all, We will have our next LIRa session on Thursday, April 1st. Our speaker is Hans van Ditmarsch. You can find the details of the talk below. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). Speaker: Hans van Ditmarsch Date and Time: Thursday, April 1st 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Everyone Knows that Everyone Knows: Gossip Protocols for Super Experts. Abstract. A gossip protocol is a procedure for sharing secrets in a network. The basic action in a gossip protocol is a telephone call wherein the calling agents exchange all the secrets they know. An agent who knows all secrets is an expert. The usual termination condition is that all agents are experts. Instead, we explore protocols wherein the termination condition is that all agents know that all agents are experts. We call such agents super experts. Additionally, we model that agents who are super experts do not make and do not answer calls. Such agents are called engaged agents. We also model that such gossip protocols are common knowledge among the agents. We investigate conditions under which protocols terminate, both in the synchronous case, where there is a global clock, and in the asynchronous case, where there is not. We show that a commonly known protocol with engaged agents may terminate faster than the same protocol without engaged agents. This is a joint work Malvin Gattinger and Rahim Ramezanian, available at https://arxiv.org/abs/2011.13203 . Hope to see you there! The LIRa team

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LIRa Session: Line van den Berg
by LIRa Seminar 24 Mar '21

24 Mar '21

Dear all, We will have our next LIRa session tomorrow. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find the details of the talk below. Speaker: Line van den Berg Date and Time: Thursday, March 25th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Multi-Agent Knowledge Evolution in Dynamic Epistemic Logic. Abstract. Agents may use their own, distinct vocabularies to reason and talk about the world, structured into knowledge representations, also called ontologies. These ontologies may be subjected to change: agents can model the world differently or learn new terms from other agents. Experimental cultural evolution offers a framework to study the mechanisms of their knowledge evolution experimentally. It has been applied to the evolution of alignments between ontologies: agents play games using alignments between their ontologies and whenever a failure in communication is reached they apply an adaptation operator - such agents will be called adaptive. In this talk, I will present a modeling of these adaptive agents in Dynamic Epistemic Logic (DEL) by (a) encoding the ontologies, (b) translating agents ontologies and alignment into knowledge and belief, (c) translating adaptation operators as announcements and conservative upgrades - these agents are called logical. The modeling enables to compare the properties of adaptive and logical agents. I will show that all but one adaptation operator are are correct, they are incomplete and partially redundant. There is a difference between the adaptive agents and logical agents: vocabulary awareness. In DEL, agents share all propositions, preventing agents to use distinct knowledge representations or to adapt them. As a solution, I introduce agent awareness using partial valuations and weakly reflexive relations. I show how to define the dynamics of awareness and show how knowledge, belief and truth are preserved through this operation. Finally, I will explain how awareness is one step to bridge the gap between adaptive and logical agents and discuss future perspectives. Hope to see you there! The LIRa team

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LIRa Session: Line van den Berg
by LIRa Seminar 19 Mar '21

19 Mar '21

Dear all, We will have our next LIRa session on Thursday, March 25th. Our speaker is Line van den Berg. You can find the details of the talk below. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). Speaker: Line van den Berg Date and Time: Thursday, March 25th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Multi-Agent Knowledge Evolution in Dynamic Epistemic Logic. Abstract. Agents may use their own, distinct vocabularies to reason and talk about the world, structured into knowledge representations, also called ontologies. These ontologies may be subjected to change: agents can model the world differently or learn new terms from other agents. Experimental cultural evolution offers a framework to study the mechanisms of their knowledge evolution experimentally. It has been applied to the evolution of alignments between ontologies: agents play games using alignments between their ontologies and whenever a failure in communication is reached they apply an adaptation operator - such agents will be called adaptive. In this talk, I will present a modeling of these adaptive agents in Dynamic Epistemic Logic (DEL) by (a) encoding the ontologies, (b) translating agents ontologies and alignment into knowledge and belief, (c) translating adaptation operators as announcements and conservative upgrades - these agents are called logical. The modeling enables to compare the properties of adaptive and logical agents. I will show that all but one adaptation operator are are correct, they are incomplete and partially redundant. There is a difference between the adaptive agents and logical agents: vocabulary awareness. In DEL, agents share all propositions, preventing agents to use distinct knowledge representations or to adapt them. As a solution, I introduce agent awareness using partial valuations and weakly reflexive relations. I show how to define the dynamics of awareness and show how knowledge, belief and truth are preserved through this operation. Finally, I will explain how awareness is one step to bridge the gap between adaptive and logical agents and discuss future perspectives. . Hope to see you there! The LIRa team

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LIRa session tomorrow: Yuri David Santos & LIRa-related A|C seminar (Sara Negri) today!
by LIRa Seminar 17 Mar '21

17 Mar '21

Dear all, We will have our next LIRa session tomorrow. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find the details of the talk below. Moreover, we would like to bring to your attention the talk of Sara Negri (today, at 16:00) at the A|C seminar. You can find the details of the talk here: http://events.illc.uva.nl/alg-coalg/ Speaker: Yuri David Santos Date and Time: Thursday, March 18th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Social Consolidations: Rational Belief in a Many-Valued Logic of Evidence and Peerhood. Abstract. We explore an interpretation of FVEL, a four-valued logic of evidence, where states represent agents, the propositional layer corresponds to the evidence available to these agents, and the relation corresponds to peerhood connections between them. Belief is determined based on the agent’s evidence, but also on her peers’ evidence. Consolidation functions are proposed, which map evidence situations to belief attitudes. We adapt some postulates of Social Choice Theory to our belief formation setting and, with them, we separate rational from irrational consolidations. We define a dynamic operator for addition and removal of evidence, which serves as a basis for some essential dynamic postulates and also for future developments on consolidations that take amounts of evidence into account. Our main technical result is a characterisation of a class of consolidations satisfying most of our rationality postulates. Hope to see you there! The LIRa team

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LIRa Session: Yuri David Santos
by LIRa Seminar 12 Mar '21

12 Mar '21

Dear all, We will have our next LIRa session on Thursday, March 18th. Our speaker is Yuri David Santos. You can find the details of the talk below. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). Speaker: Yuri David Santos Date and Time: Thursday, March 18th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: Social Consolidations: Rational Belief in a Many-Valued Logic of Evidence and Peerhood. Abstract. We explore an interpretation of FVEL, a four-valued logic of evidence, where states represent agents, the propositional layer corresponds to the evidence available to these agents, and the relation corresponds to peerhood connections between them. Belief is determined based on the agent’s evidence, but also on her peers’ evidence. Consolidation functions are proposed, which map evidence situations to belief attitudes. We adapt some postulates of Social Choice Theory to our belief formation setting and, with them, we separate rational from irrational consolidations. We define a dynamic operator for addition and removal of evidence, which serves as a basis for some essential dynamic postulates and also for future developments on consolidations that take amounts of evidence into account. Our main technical result is a characterisation of a class of consolidations satisfying most of our rationality postulates. Hope to see you there! The LIRa team

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LIRa Session: Valentin Goranko
by LIRa Seminar 10 Mar '21

10 Mar '21

Dear all, We will have our next LIRa session tomorrow. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find the details of the talk, and the link to the paper, below. Speaker: Valentin Goranko Date and Time: Thursday, March 11th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: The temporal logic of coalitional goal assignments in concurrent multi-player games. Abstract. I will present a natural extension of the Alternating time temporal logic ATL, called Temporal Logic of Coalitional Goal Assignments (TLCGA). It features just one, but quite expressive, coalitional strategic operator, called “coalitional goal assignment operator”. It is based on a mapping assigning to each set (coalition) of players in the game its coalitional goal, formalised (like in ATL) by a path formula of the language of TLCGA representing a temporalised objective for the respective coalition describing the property of the plays on which that objective is satisfied. I will illustrate the use of the logic TLCGA with some examples. In particular, I will introduce the new solution concept of “co-equilibrium”, which is particularly suitable for multi-player games with qualitative coalitional objectives, and will show that it can be naturally expressed in TLCGA. Time permitting, I will then outline our main technical results for that logic, including: fixpoint characterizations of the temporal goal assignment operators in a mu-calculus extension of TLCGA, bisimulation invariance and Hennessy-Milner property with respect to a suitably defined notion of bisimulation; a sound and complete axiomatic system, and decidability of satisfiability via finite model property. This is joint work with Sebastian Enqvist, available here: https://arxiv.org/abs/2012.14195 Hope to see you there! The LIRa team

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LIRa Session: Valentin Goranko
by LIRa Seminar 05 Mar '21

05 Mar '21

Dear all, We will have our next LIRa session on Thursday, March 11th. Our speaker is Valentin Goranko. You can find the details of the talk below. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). Speaker: Valentin Goranko Date and Time: Thursday, March 11th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: The temporal logic of coalitional goal assignments in concurrent multi-player games. Abstract. I will present a natural extension of the Alternating time temporal logic ATL, called Temporal Logic of Coalitional Goal Assignments (TLCGA). It features just one, but quite expressive, coalitional strategic operator, called “coalitional goal assignment operator”. It is based on a mapping assigning to each set (coalition) of players in the game its coalitional goal, formalised (like in ATL) by a path formula of the language of TLCGA representing a temporalised objective for the respective coalition describing the property of the plays on which that objective is satisfied. I will illustrate the use of the logic TLCGA with some examples. In particular, I will introduce the new solution concept of “co-equilibrium”, which is particularly suitable for multi-player games with qualitative coalitional objectives, and will show that it can be naturally expressed in TLCGA. Time permitting, I will then outline our main technical results for that logic, including: fixpoint characterizations of the temporal goal assignment operators in a mu-calculus extension of TLCGA, bisimulation invariance and Hennessy-Milner property with respect to a suitably defined notion of bisimulation; a sound and complete axiomatic system, and decidability of satisfiability via finite model property. This is joint work with Sebastian Enqvist, available here. Hope to see you there! The LIRa team

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LIRa Session: Frederik Van De Putte
by LIRa Seminar 03 Mar '21

03 Mar '21

Dear all, We will have our next LIRa session tomorrow. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find the details below. Speaker: Frederik Van De Putte Date and Time: Thursday, March 4th 2021, 16:30-18:00, Amsterdam time. Venue: online. Title: The Problem of No Hands: Responsibility Voids in Collective Decisions. Abstract. The problem of no hands concerns the existence of so-called responsibility voids: cases where a group makes a certain decision, yet no individual member of the group can be held responsible for this decision. Criteria-based collective decision procedures play a central role in philosophical debates on responsibility voids. In particular, the well-known discursive dilemma has been used to argue for the existence of these voids. But there is no consensus: others argue that no such voids exist in the discursive dilemma under the assumption that casting an untruthful opinion is eligible. We argue that, under this assumption, the procedure used in the discursive dilemma is indeed immune to responsibility voids, yet such voids can still arise for other criteria-based procedures. We provide two general characterizations of the conditions under which criteria-based collective decision procedures are immune to these voids. Our general characterizations are used to prove that responsibility voids are ruled out by criteria-based procedures involving an atomistic or monotonic decision function. In addition, we show that our results imply various other insights concerning the logic of responsibility voids. This is joint work with Hein Duijf. Hope to see you there! The LIRa team

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ILLC-LIRa March 2021