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
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
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
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
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
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
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
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
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
Dear all,
We will have our next LIRa session on Thursday, March 4th. Our speaker is Frederik Van De Putte. 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: 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