Events

Symplectic topology of Brieskorn singularities – Cagri Karakurt (Bogazici University)

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Abstract: Cagri will talk about some symplectic/contact topological aspects of Brieskorn singularities $x^p+y^q+z^r=0$. He’ll tell how to draw the surgery diagrams of their canonical contact structures and prove that the Milnor fiber $M(p,q,r)$ symplectically embeds into $M(p’,q’,r’)$ whenever $p\leq p’$, $q\leq q’$, and $r\leq r’$ by explicitly constructing a Stein cobordism between corresponding canonical contact

Applied Math Seminar – Qiliang Wu (Ohio University)

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Title: Pearling and Localized Undulation of Bilayers in Amphiphilic Morphology Abstract: Amphiphiles, such as lipids and functionalized polymers, plays a central role in the self-assembly of solvent accessible, intricately structured nano-scaled network structures, which are vital in cell functionality and offer wide applications to drug delivery, detergent production, emulsion stabilization and energy conversion devices. We

Analysis Seminar – Armin Schikorra (University of Pittsburgh)

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Title: A Harmonic Analysis perspective on $W^{s,p}$ as $s \to 1^-$. Abstract: We revisit the Bourgain-Brezis-Mironescu result that the Gagliardo-Norm of the fractional Sobolev space W^{s,p}, up to rescaling, converges to W^{1,p} as s\to 1. We do so from the perspective of Triebel-Lizorkin spaces, by finding sharp $s$-dependencies for several embeddings between $W^{s,p}$ and $F^{s,p}_q$

Analysis Seminar – Simon Bortz (University of Alabama)

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Title: A free boundary problem for the heat equation. Abstract: In his breakthrough result, it was shown by Dahlberg that the L^2 Dirichlet problem for the Laplacian (harmonic functions) is solvable in the region above a Lipschitz graph. Dahlberg did this by showing a local reverse Hölder inequality for the Poisson kernel in such domains.

Colloquium – Chi-Wang Shu (Brown University)

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Title: High order numerical methods for hyperbolic equations Abstract: Hyperbolic equations are used extensively in applications including fluid dynamics, astrophysics, electro-magnetism, semi-conductor devices, and biological sciences. High order accurate numerical methods are efficient for solving such partial differential equations, however they are difficult to design because solutions may contain discontinuities. In this talk we will

Algebra/Topology Seminar – Johnny Nicholson (Imperial College)

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Title: The homotopy type of a finite 2-complex with non-minimal Euler characteristic Abstract: Two presentations for a group G which have the same deficiency are called exotic if the corresponding presentation complexes are not homotopy equivalent. The first examples of exotic presentations were found by Dunwoody and Metzler in the 1970s but, owing to the difficulty of

Algebra/Topology Seminar – Orsola-Capovilla Searle (UC Davis)

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Title: Infinitely many Lagrangian Tori in Milnor fibers constructed via Lagrangian Fillings of Legendrian links Abstract: One approach to studying symplectic manifolds with contact boundary is to consider Lagrangian submanifolds with Legendrian boundary; in particular, one can study exact Lagrangian fillings of Legendrian links. There are still many open questions on the spaces of exact Lagrangian fillings

Colloquium – Francois Dufour (University of Bordeaux)

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Title: Maximizing the probability of visiting a set infinitely often for a countable state space Markov decision process Abstract: This is a joint work with Tomas Prieto-Rumeau. In this talk, we consider a Markov decision process with countable state space and Borel action space. We are interested in maximizing the probability that the controlled Markov

Algebra/Topology Seminar – Alberto Cavallo (CIRGET/Renyi Institute)

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Title: Slice links and smooth 4-manifolds Abstract: We vary the trace embedding lemma in order to prove results about smooth, closed, simply connected 4-manifolds, studying smoothly slice links in them. We focus on homotopy 4-spheres, which are potential counterexamples to the smooth 4-dimensional Poincaré conjecture. In particular, we split them, as for exotic R^4's,  in large and

Applied Math Seminar – Youngjoon Hong (Sungkyunkwan University, Korea)

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Title: Deep neural network and numerical analysis - adversarial attack on image and videos Abstract: Deep neural networks have achieved state-of-the-art performance in a variety of fields. The exponential growth of machine learning models and the extreme success of deep learning have seen application across a multitude of disciplines. Recent works observe that a class of