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Algebra seminar - November 8, 1pm, lecture room M5 PDF Print

Next algebra seminar: November 8, in M5 at 13.00.

Jovana Obradović (Charles University Prague)

Categorified cyclic operads in nature

Abstrakt:

In this talk, I will introduce a notion of categorified cyclic operad and justify the need of such a notion by exhibiting its place and use “in nature”.
Categorified cyclic operads are like symmetric monoidal categories, in that they guide an interplay of commutativity and associativity, but they are more restrictive, as they allow less instances of these two isomorphisms. In particular, the coherence conditions of symmetric monoidal categories do not ensure coherence of categorified cyclic operads, the hexagon of Mac Lane not even being well-defined in the latter setting. The coherence conditions that we do take from Mac Lane are the pentagon and the requirement that the commutator isomorphism is involutive, but we need much more in order to ensure coherence: we need two more mixed coherence conditions, a hexagon (which is not the hexagon of Mac Lane) and a decagon, as well as three more conditions which deal with the action of the symmetric group.
I will first give an example of a categorified cyclic operad in the form of an easy generalisation of the structure of profunctors of Bénabou.
I will then show how to exploit the coherence conditions of categorified cyclic operads in proving that the Feynman category for cyclic operads, introduced by Kaufmann and Ward, admits an odd version.
I will finish with combinatorial aspects of categorified cyclic operads, i.e. with their possible characterisations in convex and discrete geometry. This investigation aims at finding polytopes which describe the coherences of categorified cyclic operads, in the same was as the geometry of symmetric monoidal categories is demonstrated by permutoassociahedra.

Last Updated on Monday, 29 October 2018 16:08
 
Differential equations seminar - November 5, 12pm, lecture room M5 PDF Print

Seminar of differential equations will continue on November 5, 2018 at 12pm in lecture room M5.

Mgr. Jana Burkotová, Ph.D.

Periodic bouncing solutions of singular second order ODE.

Last Updated on Friday, 26 October 2018 07:55
 
Seminar - October 25, 1pm, lecture room M5 PDF Print

Our Algebra seminar will continue on Thursday, October 25, at 13.00 in M5 by the talk

S. Henry

Transfinite constructions in infinity categories

I'll present an adaptation in infinity categorical context of some classical "transfinite constructions" in category theory: the construction of the free algebras for a (pointed,well pointed) endofunctor and the construction of colimits in the category of algebras for a monad. A large part of the talk will be a basic introduction to infinity category theory (quasi-category theory) and to the Riehl-Verity theory of infinity-monads. The goal is mostly to give some example of what it look like to works with infinity categories and how it changes from ordinary category theory.

 
Seminar - October 22, 10am, lecture room M5 PDF Print

The seminar on differential geometry will continue on October 22 in the lecture room M5 by the lecture:

Ilya Kossovskiy:

Real analytic coordinates for smoothly embedded CR hypersurfaces.

Last Updated on Tuesday, 16 October 2018 08:50
 
Seminar - October 10, Prof. Javier Esparza, TU Munich PDF Print

Prof. Javier Esparza

TU Munich, an ERC advanced grant holder, and a Honorary doctor of Masaryk University (among his many other distinguished honors).

The lecture will be in the Mendel Museum (not FI!) on * Wednesday Oct 10, since 16:00.

Black Ninjas in the Dark: Analyzing Population Protocols

Abstract:

Population protocols are a mathematical model of distributed computation introduced by Angluin et al. in 2004. The original purpose of Angluin et al. was the theoretical study of systems consisting of identical, cheap mobile devices with tiny computational resources, like sensor networks. However, since its introduction, the model has also been used to analyze the behavior of chemical systems and people in social networks. Population protocols help us to pose and study many fundamental questions about distributed systems: What can be computed by agents wishing to remain anonymous? Are leader processes necessary for optimal speed? Can macroscopic "phase transitions" be "programmed" at a microscopic level? Is it possible to check automatically that a protocol works correctly? Is it possible to automatically synthesize a protocol for a given task?

In the talk, I will introduce the population protocol model with the help of several examples. More precisely, I will present the problem of the Black Ninjas in the Dark, and the different solutions given to it by their Senseis. I will also show animated simulations of some protocols.

 
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