Graduate student seminar

The seminar takes place at room MaD380 at 14:15–15:15, unless otherwise stated. Everyone is welcome.

If you are willing to give a talk or have any questions you can contact Timo Schultz or Ville Kivioja.

Back to seminar 2022.

Talks in Autumn 2017

22.9. Illusionary contours and subRiemannian geometry

Ville Kivioja

Abstract

I will consider the Citti--Sarti--Petitot model for the image completion in the primary visual cortex of humans. This model, based on subRiemannian geometry of the rototranslation group, explains in particular quantitatively the appearences of illusonary contours in, for example, the Kanizsa Triangle. I will show how, and I will introduce the necessary concepts of biology and subRiemannian geometry along the way.

29.9. On free groups

Timo Schultz

Abstract

I will prove that the subgroups of a free group are free. This is done using the fundamental group, theory of covering spaces and graph theory.

6.10. Nonlinear eigenvalue problems

Shirsho Mukherjee

Abstract

The topics that shall be discussed, will mainly involve the notion of non-linear eigenvalues and ways of generating such eigenvalues under invariance with respect to compact symmetry groups, acting on Finsler manifolds.

13.10. Interesting 3-dimensional topology

Atte Lohvansuu

Abstract

I will present some interesting facts about the topology of orientable compact connected 3-manifolds: the existence of a Heegaard splitting and the Lickorish-Wallace theorem, which states that any such manifold can be obtained by performing surgeries on the 3-dimensional sphere.

20.10. Interpolation in Banach spaces

Debanjan Nandi

Abstract

We will discuss Interpolation (real) in Banach spaces of functions and consider some examples.

27.10. Uniformization of Riemann surfaces

Toni Ikonen

Abstract

I will introduce a Uniformization Theorem for general Riemann surfaces and some of its corollaries. The proof uses some algebraic topology and the Uniformization Theorem for simply-connected Riemann surfaces.

3.11. Composition operator and the extension of Sobolev function from cusps to the plane

Zheng Zhu

Abstract

According to several results of Shvartsman, Koskela, Rajala and Zhang, we can obtain that the inward cusp domain in plane is $W{1,1}$-extension. Also we find that both outward and inward cusp domains do not satisfies the sufficient condition for the extension of $W{1,p}$ for $p>1$. Then the interesting problem is that what is the optimal Sobolev-extension results for these two kinds of cusp domains, than means, if we extend $W{1,p}$ outside to get a function belonging to $W{1,q}(\mathbb{R}{2})$, what is the optimal upper bound for $q$? Obviously, we have $q < p$.

10.11. A guide to option pricing via tug-of-war games

Joonas Heino

Abstract

In this talk, I will introduce option pricing in the context of a two-player zero-sum stochastic differential game in a multi-dimensional financial market. In the original Black-Scholes model, the arbitrage free price of an option is the unique solution to the Cauchy problem for a linear second order uniformly parabolic equation (heat equation). However, in this new game context, the underlying PDE is much more involved due to the presence of the nonlinear and degenerate infinity Laplace operator.

17.11. Regularity of harmonic functions

Martti Rasimus

Abstract

I will discuss standard regularity results for (quasi-)minimizers of the p-Dirichlet energy in the non-standard setting of general metric measure spaces.

24.11. Trace spaces of some function spaces

Zhuang Wang

Abstract

In the talk, I will introduce some classical results about the trace spaces of some function spaces, like Sobolev space, Besov space. I will also give a proof of the trace result of Sobolev space.

1.12. The minimal number of generators for ideals in polynomial rings

Erika Pirnes

Abstract

Let R be a Noetherian ring (every ideal is finitely generated). Consider the polynomial ring over R with n variables. Let J be an ideal in this polynomial ring generated by some set of polynomials. The goal of my master's thesis is to find (or at least estimate) the minimal number of polynomials needed to generate J.