Seminar  November 12, 10am, lecture room M5 


The seminar on differential geometry will continue by the following lecture:
November 12 (10.00, M5)
Artur Sergyeyev (SU Opava)
Hydrodynamic Integrability: from Symplectic to Contact Geometry
Abstract:
We begin with a brief introduction to integrable systems in general and a review of known results on the construction of integrable hydrodynamictype partial differential systems in three independent variables with Lax pairs involving Hamiltonian vector fields. Then we present a generalization of this construction to the case of four independent variables, where Hamiltonian vector fields are replaced by contact ones, and show that this approach gives rise to a large new class of integrable hydrodynamictype systems. 
Last Updated on Tuesday, 30 October 2018 13:14 

Algebra seminar  November 8, 1pm, lecture room M5 


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 welldefined 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 


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 


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 (quasicategory theory) and to the RiehlVerity theory of infinitymonads. 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 


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 

