Dear all,

Next Thursday, June 10th, we have two events of interest to the LIRa audience. The first is the DIEP talk of Casper van Elteren, from 11:00 to 12:30. The second is our LIRa session with Jiatu Li, which will take place on 15:00-16:30 (note the UNUSUAL TIME compared to our regular sessions!). You can find the details for both events, as well as their zoom links, below. ----------------------------------------------------- Date and time: Thursday, June 10th 2021, 11:00-12:30, Amsterdam time. Speaker: Casper van Elteren (UvA) Title: Through the looking glass - Information flows in complex systems

Abstract: Understanding dynamical systems is a fundamental problem for the 21st century. Despite the prima facie differences and purposes of many real-world networks, previous research shows several universal characteristics in networks properties such as the small-world phenomenon, fat-tail degree and feedback loops. This has led to the common but often implicit assumption that the connectedness of a node in the network is proportional to its dynamic importance. For example in epidemic research, high degree nodes or "super-spreaders" are associated to dominant epidemic risk and therefore deserve special attention. Yet prior research shows that the shared universality in network characteristics is not shared in the dynamic or functional properties of many real-world systems.

In this talk I will explore the relation between local interactions and macroscopic properties of a system through the lens of statistical physics and information theory. In particular, I will show novel methods on determining the so-called driver node in complex systems, and how tipping points can be studied from an information theoretical perspective. (website + slides: https://cvanelteren.github.io/talk/diep2021/)

Zoom link: https://uva-live.zoom.us/j/85608909905 -----------------------------------------------------

Speaker: Jiatu Li Date and Time: Thursday, June 10th 2021, 15:00-16:30, Amsterdam time. Venue: online. Title: Formalization of PAL in Lean.

Abstract.

Proof assistant (or theorem prover) is a useful tool to organize and check formal mathematical proofs. Despite of several impressive stories, it still seems hopeless for common mathematicians to use it for their daily work. However, it may be handy for logicians in some certain applications, for example, in developing proof systems. In this talk, we will demonstrate a formalization of public announcement logic (including syntax, semantics, a proof system and meta-theorems including soundness and completeness) in Lean theorem prover. We will also discuss in general the potential applications of proof assistant in logic research.

Recurring zoom link: https://uva-live.zoom.us/j/92907704256?pwd=anY3WkFmQVhLZGhjT2JXMlhjQVl1dz09 (Meeting ID: 929 0770 4256, Passcode: 036024)

Hope to see you there!

The LIRa team