ILLC-LIRa November 2020

illc-lira@list.uva.nl

1 participants
9 discussions

LIRa/GroLog Logic Afternoon
by LIRa Seminar 27 Nov '20

27 Nov '20

Dear all, Next Thursday, we will have a joint LIRa-GroLog (https://sites.google.com/rug.nl/grolog/home) Logic Afternoon! Our speakers will be Zoé Christoff from University of Groningen and Aybüke Özgün from University of Amsterdam. You can find the schedule and the details of the talks below. We will use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). Speakers: Zoé Christoff (University of Groningen) and Aybüke Özgün (University of Amsterdam) Date and Time: Thursday, December 3rd 2020, 15:30-17:30, Amsterdam time. Schedule: 15:30 Arrival 15:45 First talk 16:30 Break 16:45 Second talk 17:30 Drinks Venue: online. Zoé Christoff: Group Knowledge in Epistemic Logic with Names (joint work with Marta Bílková and Olivier Roy) In many situations, we refer to a group of agents using a label, say \"Trump supporters\" or \"trolls\", without knowing exactly who the members of the group are. Sometimes, we even fail to know whether we, ourselves, are members of a given group. Yet, epistemic logic typically comes with the simplifying assumption that group membership is common knowledge among the entire population. In 1993 already, Grove and Halpern introduced a generalized epistemic logic relaxing this assumption and replacing the usual indexes to denote agents with abstract names that can have different referents, both individuals or groups, in different possible worlds. In that generalized framework, they replace the standard K_i modalities with modalities of the form S_n and E_n, for \"someone with name n knows\" and \"everyone with name n knows\", respectively. In our current work, we discuss extensions of this generalized logic with group modalities for common knowledge and distributed knowledge. Reference: A. J. Grove and J. Y. Halpern. Naming and Identity in Epistemic Logics Part I: The Propositional Case. Journal of Logic and Computation, 3(4):345–378, 08, 1993. Aybüke Özgün: Uncertainty about Evidence We develop a logical framework for reasoning about knowledge and evidence in which the agent may be uncertain about how to interpret their evidence. Rather than representing an evidential state as a fixed subset of the state space, our models allow the set of possible worlds that a piece of evidence corresponds to to vary from one possible world to another, and therefore itself be the subject of uncertainty. Such structures can be viewed as (epistemically motivated) generalizations of topological spaces. In this context, there arises a natural distinction between what is actually entailed by the evidence and what the agent knows is entailed by the evidence---with the latter, in general, being much weaker. We provide a sound and complete axiomatization of the corresponding bi-modal logic of knowledge and evidence entailment, and investigate some natural extensions of this core system, including the addition of a belief modality and its interaction with evidence interpretation and entailment, and the addition of a “knowability\" modality interpreted via a (generalized) interior operator. This is joint work with Adam Bjorndahl. Hope to see you there! The LIRa team

1 0

Two LIRa-related events this Thursday!
by LIRa Seminar 24 Nov '20

24 Nov '20

Dear all, This Thursday we have two LIRa-related events. One is the announced LIRa talk by Andres Occhipinti, with title: Learning to Act and Observe in Partially Observable Domains. This will take place at the regular time (16:30-18:00), and you can use our recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024). You can find more details below. The second event (taking place in fact earlier on Thursday) is the workshop of DIEP (Dutch Institute for Emergent Phenomena), between 13:00-16:00, which includes a talk by ILLC-based DIEP fellow Soroush Rafiee Rad, who is soon to join our group, and who will give a talk with title: Characterizing Probabilistic Models with a Symmetry Axiom\" (at 14:20). The zoom link for this second event is: https://uva-live.zoom.us/j/87881838105 More details follow below. ----------------------------------------------------------------------------------------- Regular LIRa TALK: Andres Occipinti Liberman Date and Time: Thursday, November 26th 2020, 16:30-18:00, Amsterdam time. Title: Learning to Act and Observe in Partially Observable Domains Abstract: We consider a learning agent in a partially observable domain (or environment), with which the agent has never interacted before. The agent wishes to learn a representation of the domain dynamics: how the agent\\\'s actions affect the state of the domain and what becomes observable as a result of such actions. To produce such knowledge, the learner has access to experience gathered by taking actions in the domain and observing their results. We present algorithms for learning \\\"as much as possible\\\" (in a well-defined sense) both about what is directly observable and about what actions do in the domain, given the learner\\\'s observational constraints. We differentiate the level of domain knowledge attained by each algorithm, and characterize the type of observations required to reach it. The algorithms use dynamic epistemic logic (DEL) to represent the learned domain information symbolically. Our work continues that of Bolander and Gierasimczuk (2015), which developed DEL-based learning algorithms based to learn domain information in fully observable domains. This is joint work with Thomas Bolander and Nina Gierasimczuk. --------------------------------------------------------------------------------------- LIRa-related event: DIEP Workshop (including talk by Soroush Rafiee Rad) Date and Time: Thursday, November 26th 2020, 13:30-16:00, Amsterdam time. Soroush\'s talk is at 14:20. On Thursday, the 26th of November from 1pm to 4pm, the Dutch Institute for Emergent Phenomena (DIEP) is organising a series of virtual talks by the DIEP fellows and researchers who will be joining DIEP@UvA soon. ILLC is the host institute for one of these fellows, Soroush Rafiee Rad, who will give a talk on ``Characterizing Probabilistic Models with a Symmetry Axiom\". The topics covered by the talks include multiscale modelling of reaction-diffusion networks, self-learning algorithms in duopoly, axiomatic approaches to probabilistic models, and many-body stochastic systems. Everybody is welcome to attend, and the Zoom link is https://uva-live.zoom.us/j/87881838105 You will have the opportunity to meet DIEP researchers and hear more about upcoming activities. More information (including full programme and abstracts) is available here: https://www.d-iep.org/diepuvakickoff Hope to see you there! The LIRa team

1 0

LIRa session RESCHEDULED: Andrés Occhipinti Liberman
by LIRa Seminar 19 Nov '20

19 Nov '20

Dear all, Unfortunately, we have to cancel the LIRa session originally scheduled for today. Our speaker, Andrés Occhipinti Liberman, agreed to reschedule the talk for next week, Thursday 26th of November. See you then and apologies for any inconvenience! The LIRa team

1 0

LIRa session (online only): Andrés Occhipinti Liberman
by LIRa Seminar 18 Nov '20

18 Nov '20

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. Date and Time: Thursday, November 19th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: Learning to Act and Observe in Partially Observable Domains Abstract. We consider a learning agent in a partially observable domain (or environment), with which the agent has never interacted before. The agent wishes to learn a representation of the domain dynamics: how the agent\'s actions affect the state of the domain and what becomes observable as a result of such actions. To produce such knowledge, the learner has access to experience gathered by taking actions in the domain and observing their results. We present algorithms for learning \"as much as possible\" (in a well-defined sense) both about what is directly observable and about what actions do in the domain, given the learner\'s observational constraints. We differentiate the level of domain knowledge attained by each algorithm, and characterize the type of observations required to reach it. The algorithms use dynamic epistemic logic (DEL) to represent the learned domain information symbolically. Our work continues that of Bolander and Gierasimczuk (2015), which developed DEL-based learning algorithms based to learn domain information in fully observable domains. This is joint work with Thomas Bolander and Nina Gierasimczuk. Hope to see you there! The LIRa team

1 0

LIRa session (online only): Andrés Occhipinti Liberman
by LIRa Seminar 14 Nov '20

14 Nov '20

Dear all, We will have our next LIRa session on Thursday, November 19th. Our speaker is Andrés Occhipinti Liberman. 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). Date and Time: Thursday, November 19th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: Learning to Act and Observe in Partially Observable Domains Abstract. We consider a learning agent in a partially observable domain (or environment), with which the agent has never interacted before. The agent wishes to learn a representation of the domain dynamics: how the agent\'s actions affect the state of the domain and what becomes observable as a result of such actions. To produce such knowledge, the learner has access to experience gathered by taking actions in the domain and observing their results. We present algorithms for learning \"as much as possible\" (in a well-defined sense) both about what is directly observable and about what actions do in the domain, given the learner\'s observational constraints. We differentiate the level of domain knowledge attained by each algorithm, and characterize the type of observations required to reach it. The algorithms use dynamic epistemic logic (DEL) to represent the learned domain information symbolically. Our work continues that of Bolander and Gierasimczuk (2015), which developed DEL-based learning algorithms based to learn domain information in fully observable domains. This is joint work with Thomas Bolander and Nina Gierasimczuk. Hope to see you there! The LIRa team

1 0

Online Workshop tomorrow: Logic with Vector Space Models
by LIRa Seminar 12 Nov '20

12 Nov '20

Dear all, The LIRa-related event \"Logic with Vector Space Models\" will take place online tomorrow, November 13. The zoom link is: https://zoom.us/j/99494442845?pwd=K0ZWZXlpWlJJRENlV0RRYUdONlBDQT09 (Meeting ID: 994 9444 2845, Passcode: 995763). Please, find the general information below. For more details: http://tsinghualogic.net/JRC/?p=2001 Vector space, as a mathematical structure, is perhaps much more understood by human beings than any other field of mathematics, and it finds its natural usage in a number of wildly different areas, including physics, computer science, numerical analysis, linguistics, to name a few. Logic, on the other hand, is the canonical tool for talking about and reasoning in different structures. Given that vector space is used as the fundamental structure at various places, a complete analysis of it using logical tools and the development of logical systems with vector space models will be beneficial. The goal of this workshop is to bring together worldwide scholars who share a common interest in this topic but with varying perspectives, collaborating to develop tools for logical analysis of vector spaces or logical systems with vector space models. We hope this workshop will broaden our views on the matter of subject, and ultimately put logic and logical methods in a place of wider applications. Hope to see you there! The LIRa team

1 0

LIRa session (online only): Andrey Kudinov tomorrow (and workshop on Friday!)
by LIRa Seminar 11 Nov '20

11 Nov '20

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 attached below. Notice that this week there is another event that might be interesting for the LIRa audience, namely the Online Workshop: Logic with Vector Space Models. It will take place online on November 13. More details: http://tsinghualogic.net/JRC/?p=2001 and zoom link: https://zoom.us/j/99494442845?pwd=K0ZWZXlpWlJJRENlV0RRYUdONlBDQT09 (Meeting ID: 994 9444 2845, Passcode: 995763). Date and Time: Thursday, November 12th 2020, 16:30-18:30, Amsterdam time. Venue: online. Title: Neighborhood products of modal logics Abstract. The product of modal logics is often considered in the context of multidimensional modal logics. It is defined as the logic of two-dimensional structures, usually, the product of Kripke frames. But there are other semantics for modal logic. Van Benthem with coauthors (2005, “Multimodal Logics of Products of Topologies”) defined the product of topological spaces and topological product of modal logics for extensions of S4. Note that this product of topological spaces is a bitopological space, it has horizontal and vertical topologies that are different from the product topology. These definitions were later extended to monotone modal logics by Sano (2011, “Axiomatizing Hybrid Products of Monotone Neighborhood Frames”) by defining the product of monotone neighborhood frames. For extension of S4 the neighborhood frames are equivalent to topological spaces. It turned out that, in general, the neighborhood product of modal logics is weaker than Kripke products. For example the neighborhood (topological) product of S4 with S4 is the fusion of S4 with S4. Later in 2012 and in 2016 the speaker proved that for many serial normal modal logics the neighborhood product coincides with the fusion. And for non-serial logics the neighborhood product of modal logics should include some list of variable-free formulas. The way we prove completeness for neighborhood products of modal logics is based on Kripke completeness. For a given Kripke frame we construct a neighborhood frame of pseudo infinite paths in the Kripke frame. The details will be given in the talk. I think that this construction has a nice epistemic intuition which I would like to discuss with the participants of the seminar during and/or after my talk. In the talk I will formulate several completeness results that were proved by the speaker, including some results about derivational topological semantics. . Hope to see you there! The LIRa team

1 0

LIRa session (online only): Andrey Kudinov
by LIRa Seminar 06 Nov '20

06 Nov '20

Dear all, We will have our next LIRa session on Thursday, November 12th. Our speaker is Andrey Kudinov. 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). Date and Time: Thursday, November 12th 2020, 16:30-18:30, Amsterdam time. Venue: online. Title: Neighborhood products of modal logics Abstract. The product of modal logics is often considered in the context of multidimensional modal logics. It is defined as the logic of two-dimensional structures, usually, the product of Kripke frames. But there are other semantics for modal logic. Van Benthem with coauthors (2005, “Multimodal Logics of Products of Topologies”) defined the product of topological spaces and topological product of modal logics for extensions of S4. Note that this product of topological spaces is a bitopological space, it has horizontal and vertical topologies that are different from the product topology. These definitions were later extended to monotone modal logics by Sano (2011, “Axiomatizing Hybrid Products of Monotone Neighborhood Frames”) by defining the product of monotone neighborhood frames. For extension of S4 the neighborhood frames are equivalent to topological spaces. It turned out that, in general, the neighborhood product of modal logics is weaker than Kripke products. For example the neighborhood (topological) product of S4 with S4 is the fusion of S4 with S4. Later in 2012 and in 2016 the speaker proved that for many serial normal modal logics the neighborhood product coincides with the fusion. And for non-serial logics the neighborhood product of modal logics should include some list of variable-free formulas. The way we prove completeness for neighborhood products of modal logics is based on Kripke completeness. For a given Kripke frame we construct a neighborhood frame of pseudo infinite paths in the Kripke frame. The details will be given in the talk. I think that this construction has a nice epistemic intuition which I would like to discuss with the participants of the seminar during and/or after my talk. In the talk I will formulate several completeness results that were proved by the speaker, including some results about derivational topological semantics. . Hope to see you there! The LIRa team

1 0

LIRa session: Mehrnoosh Sadrzadeh
by LIRa Seminar 04 Nov '20

04 Nov '20

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). Date and Time: Thursday, November 5th 2020, 16:30-18:00, Amsterdam time. Venue: online. Title: Linguistic Random Matrix Theory Abstract. Constructions in type-driven compositional distributional semantics associate large collections of matrices of size D to linguistic corpora. Following the work of Wigner and Dyson on developing random matrix theory for analysing energy levels of nuclei using distributions of matrices of random variables, we develop the proposal of analysing the statistical characteristics of linguistic data in the framework of permutation invariant matrices. The observables in this framework are permutation invariant polynomial functions of the matrix entries, which correspond to directed graphs. Using the general 13-parameter permutation invariant Gaussian matrix models recently solved, we find, using a dataset of matrices constructed via standard techniques in distributional semantics, that the expectation values of a large class of cubic and quartic observables show high gaussianity at levels between 90 to 99 percent. We find evidence that observables with similar matrix model characteristics of gaussianity also have high degrees of correlation between the ranked lists of words associated to these observables. This is joint work with Ramgoolam and Sword from String Theory in QMUL and with Kartsaklis from Apple. Hope to see you there! The LIRa team

1 0

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

ILLC-LIRa November 2020