# MSCS Seminar Calendar

Monday August 31, 2015
Model Theory Seminar
First-order theories of II$_1$ factors-Part II
Isaac Goldbring (UIC)
2:00 PM in SEO 427
I will speak on a recent preprint (http://arxiv.org/pdf/1507.06340.pdf) proving that there are continuum many theories of II$_1$ factors. I will introduce all necessary background from the theory of von Neumann algebras.

Organizational Meeting
Trevor Leslie (UIC)
3:00 PM in SEO 612

An Introduction to the Theory of Cryptography
4:00 PM in SEO 636
This talk will be a brief introduction to the beautiful theoretical results in cryptography. Time permitting, we will answer questions such as: 1. Can you have perfect encryption? (Spoiler: yes, but it is impractical.) 2. Is there a notion of security that is practical but still hard enough to break? If so, can we achieve it? 3. Can we algorithmically generate pseudo-random bits? How random is random enough? 4. Is it possible to convince someone you proved the Riemann hypothesis without revealing any information at all about the proof itself? 5. You are talking to your friend on the phone and you want to decide an important question by flipping a coin. How can you make sure that your friend didn't lie about the result of the coin toss?
Tuesday September 1, 2015
Logic Seminar
Hindman’s theorem and idempotent types
Isaac Goldbring (UIC)
4:00 PM in SEO 427
For a set A of natural numbers, let FS(A) denote the set of sums of finitely many distinct elements of A. A set B of natural numbers is said to be an IP set if B contains FS(A) for some infinite set A. A central result in combinatorial number theory is Hindman's theorem, which states that if one finitely colors an IP set, then at least one of the colors is an IP set. The slickest proof of this result uses idempotent ultrafilters. Di Nasso suggested a model-theoretic generalization of idempotent ultrafilters, aptly named idempotent types, and asked in what completions of PA idempotent types exist. In this talk, I will show that Hindman's theorem is actually equivalent to the existence of idempotent types in all countable complete extensions of PA. This has potential philosophical consequences that I will also discuss. This is joint work with Uri Andrews.
Wednesday September 2, 2015
Homotopy Theory Seminar
Computations in algebraic K-theory
Benjamin Antieau (UIC)
2:00 PM in SEO 1227
I will survey some of the state of the art approaches to computing the algebraic K-theory of rings and schemes. This will include both rational perspectives and characteristic p methods such as the use of the Steenrod algebra, and it will give a kind of road map for where the seminar will go this semester.

Pathologies on surfaces in characteristic $p$, or how I found someone's paper is wrong
Xudong Zheng (UIC)
3:00 PM in SEO 712
In this talk, I will present some constructions of algebraic surfaces in characteristic $p$ which violate the Kodaira vanishing theorem. These surfaces also provide counterexamples to Fujita's positivity theorem for fibered surfaces. Further pathologies on these examples include the existence of non-closed global differential 1-forms and global vector fields, which are both known to be impossible in characteristic zero. I will survey the comparison of characteristic zero with characteristic $p$, sketch the construction, and mention how I encountered these results by noticing errors in a recent published paper.

Graduate Geometry, Topology and Dynamics Seminar
van Kampen's Theorem and Group actions on Trees
Edgar A. Bering IV (UIC)
3:00 PM in SEO 612
Starting with van Kampen's theorem we trace how a group splitting gives rise to an action on a tree. We will survey (but probably not prove) converses and related structure theorems for groups one can obtain when the group acts on a tree. This talk will be accessible to anyone with a familiarity with van Kampen's theorem.

Social choice theory and Fourier analysis: a simple proof of Arrow's Impossibility Theorem
Ben Fish (UIC)
3:00 PM in SEO 427
This talk will give an introduction to social choice theory, a theoretical framework for studying how to aggregate individual preferences into a social welfare function, concentrating on Arrow's Impossibility Theorem. This talk will present a proof of this theorem (due to Kalai, 2002) using the Fourier analysis of Boolean functions, which is both a surprising and elegant application of Fourier analysis.

Statistics Seminar
Organizational Meeting
Statistics Faculty & Students (UIC)
4:00 PM in SEO 636

Algebraic Geometry Seminar
Stability Conditions on Threefolds - Some Wall-Crossings
Benjamin Schmidt (Ohio State University)
4:00 PM in SEO 427
The theory of Bridgeland stability conditions has lead to deep results about the geometry of moduli spaces of sheaves on surfaces. One of the main obstacles to do the same on threefolds is the construction of stability conditions. Recent progress on this question in special cases raises the question whether the corresponding moduli spaces can be studied. I will present an approach that uses computations similar to those on surfaces. In the case of projective space, I will show examples of concrete wall-crossing behavior for some Hilbert schemes of curves.
Thursday September 3, 2015
Quantum Topology / Hopf Algebra Seminar
Rotational Virtual Knots and Quantum Invariants of Knots
Louis H Kauffman (UIC)
3:00 PM in SEO 612
We define rotational virtual knots and show how the KRH formulation of quantum invariants of knots and links fits precisely this diagrammatic category. Thus rotational virtuals are the most natural test category for quantum invariants.
Tuesday September 8, 2015
Logic Seminar
A super-Dowker filter
James Cummings (CMU)
4:00 PM in SEO 427
A super-Dowker filter is a filter F on a set X such that
1) For every sequence of F-large sets there are x,y distinct with x in A_y and y in A_x
2) For every partition of X into two parts there exist a sequence as in 1) and a cell of the partition such that all pairs as in 1) lie in this cell
Building on work of Balogh and Gruenhage we show the consistency of the existence of a super-Dowker filter.
Wednesday September 9, 2015
Homotopy Theory Seminar
The trace map K(A) -> THH(A) and the Bökstedt spectral sequence
Xing Gu (UIC)
2:00 PM in SEO 1227

Graduate Geometry, Topology and Dynamics Seminar
New Density Bounds and Optimal Ball Packings for Hyperbolic Space
Robert Kozma (UIC)
3:00 PM in SEO 612
We consider ball packings of hyperbolic space, motivating the discussion with recent developments in three dimensions. We then show that it is possible to exceed the conjectured $4$-dimensional packing density upper bound due to L. Fejes-T\'oth (Regular Figures, 1964). We give several examples of horoball packing configurations that yield higher densities of $\approx 0.71$ where horoballs are centered at the ideal vertices of certain Coxeter simplex tilings.

Statistics Seminar
TBA
Nick Syring (UIC)
4:00 PM in SEO 636

Algebraic Geometry Seminar
Calabi-Yau threefolds fibred by lattice polarized K3 surfaces
Alan Thompson (University of Waterloo)
4:00 PM in SEO 427
I will describe recent joint work with C. Doran, A. Harder and A. Novoseltsev, in which we study the moduli spaces of certain Calabi-Yau threefolds with small Hodge number $h^{2,1}$. Many such Calabi-Yau threefolds admit fibrations by K3 surfaces that are polarized by lattices of high rank. In the case where the polarizing lattice has rank 19, the theory of such fibrations closely parallels the theory of elliptic surfaces: in particular, the coarse moduli space of the K3 surface fibres is a modular curve, and there are analogues of the functional and homological invariants which determine much of the geometry of the threefold total space. Using this structure, it is possible to explicitly map out the moduli spaces of Calabi-Yau threefolds fibred by such K3 surfaces. There is also a beautiful interpretation of mirror symmetry for these Calabi-Yau threefolds, related to (weak) Landau-Ginzburg models of Fano threefolds, which I will describe if time allows.
Monday September 14, 2015
Geometry, Topology and Dynamics Seminar
TBA
Brian Collier (University of Illinois at Urbana Champaign)
3:00 PM in SEO 636

Analysis and Applied Mathematics Seminar
Semiclassical approximations to quantum mechanical expectation values
Wolfgang Gaim (University of Tübingen)
4:00 PM in SEO 636
In his 1932 paper, Eugene Wigner introduced the now famous Wigner function in order to compute quantum corrections to classical equilibrium distributions. We show how to extend this program and compute semiclassical approximations to time evolved quantum observables as well as quantum mechanical equilibrium distributions for slow, semiclassical degrees of freedom coupled to fast, quantum mechanical degrees of freedom. The main examples are molecules and electrons in crystalline solids. The semiclassical formulas contain, in addition to quantum corrections similar to those of Wigner, also modifications of the classical Hamiltonian system used in the approximation: The classical energy and the Liouville measure on classical phase space turn out to have non-trivial-expansions in the semiclassical parameter. This talk is based on joint work with Stefan Teufel.
Tuesday September 15, 2015
Logic Seminar
TBA
Daniel Palacín (University of Münster)
4:00 PM in SEO 427
Wednesday September 16, 2015
Homotopy Theory Seminar
The Steenrod algebra
Joe Berner (UIC)
2:00 PM in SEO 1227

Geometry, Topology and Dynamics Seminar
Knottedness is in NP, modulo GRH
Greg Kuperberg (UC Davis)
3:00 PM in SEO 636
In this talk I will discuss my result that confirming that a knot diagram is a non-trivial knot is in the complexity class NP, assuming the Generalized Riemann Hypothesis. Time permitting, I will also discuss related results, in particular the earlier result of Hass, Lagarias, and Pippenger that unknottedness is in NP. Everything will be on the theme of qualitative complexity theory in geometric topology, in other words, what you can compute in polynomial time with help.

Statistics Seminar
Mock Oral Exam
Stat Faculty and Students (UIC)
4:00 PM in SEO 636

Algebraic Geometry Seminar
TBA
Jinhyun Park (KIAST)
4:00 PM in SEO 427
Thursday September 17, 2015
Quantum Topology / Hopf Algebra Seminar
How hard is it to approximate the Jones polynomial?
Greg Kuperberg (UC Davis)
3:00 PM in SEO 612
The short answer is that it's #P-hard.   The longer answer is that it was an algorithm was constructed in the quantum computation community to approximate the Jones polynomial at a principal root of unity, except with a diagram-dependent normalization factor.   I will present my result that if you strip away this normalization factor to ask for any fair approximation, then approximating the Jones polynomial is as hard as any combinatorial counting problem and almost certainly out of reach for classical or even quantum computers.   It is conjectured that the Jones polynomial distinguishes the unknot, but we can envision that we can know whether a complicated knot diagram is an unknot long before we know much about its Jones polynomial.
Monday September 21, 2015
Analysis and Applied Mathematics Seminar
Perturbation theory for discrete eigenvalues: Kato-Rellich theory and asymptotic expansions
George Nenciu (Institute of Mathematics of the Romanian Academy)
4:00 PM in SEO 636
Basic facts of Kato-Rellich regular perturbation for discrete eigenvalues are briefly reviewed. For singular perturbations (e.g. anharmonic oscillator, Stark effect) asymptotic expansions for the perturbed projections leading to (almost) invariant subspaces are provided.
This is a two hour introductory talk intended mainly for graduate students.
Wednesday September 23, 2015
Homotopy Theory Seminar
Dyer-Lashof operations and H-infinity ring spectra
Maximilien Holmberg-Péroux (UIC)
2:00 PM in SEO 1227

Statistics Seminar
TBA
Daniel Conus (Lehigh University)
4:00 PM in SEO 636

Algebraic Geometry Seminar
NO SEMINAR
----------
4:00 PM in SEO 427
Friday September 25, 2015
Algebraic Geometry Seminar
TBA
Chih-Chi Chou (University of Washington)
1:00 PM in SEO 427
Monday September 28, 2015
Combinatorics Seminar
The critical exponent of a graph
Apoorva Khare (Stanford University)
3:00 PM in SEO 427
We classify the powers that preserve positive semidefiniteness, when applied entrywise to matrices with rank and sparsity constraints. This is part of a broad program to study entrywise functions preserving positivity on distinguished submanifolds of the cone. In our first main result, we completely classify the powers preserving Loewner properties on positive semidefinite matrices with fixed dimension and rank. This includes the case where the matrices have negative entries. Our second main result characterizes powers preserving positivity on matrices with zeros according to a chordal graph. We show how preserving positivity relates to the geometry of the graph, thus providing interesting connections between combinatorics and analysis. The work has applications in regularizing covariance/correlation matrices, where entrywise powers are used to separate signal from noise, while minimally modifying the entries of the original matrix. (Based on joint work with D. Guillot and B. Rajaratnam, Stanford.)

Analysis and Applied Mathematics Seminar
Perturbation theory for embedded eigenvalues: Rayleigh-Schrödinger expansion, spectral concentration and metastable states.
George Nenciu (Institute of Mathematics of the Romanian Academy)
4:00 PM in SEO 636
Perturbation theory for embedded eigenvalues and exponential decay for resulting metastable states are considered. The relations between the formal Rayleigh-Schrödinger expansion, spectral concentration and decay law for metastable states are discussed in the smooth setting. The main result is that if the FGR constant vanishes then the first order correction in the Rayleigh-Schrödinger expansion is well defined and the exponential decay law for the corresponding metastable state has both the decay rate and error term of order $\epsilon^4$ where $\epsilon$ is the perturbation strength.
Tuesday September 29, 2015
Logic Seminar
TBA
Dima Sinapova (UIC)
4:00 PM in SEO 427
Wednesday September 30, 2015
Homotopy Theory Seminar
The topological Hochschild homology of finite fields I
Özgür Bayindir (UIC)
2:00 PM in SEO 1227

Statistics Seminar
TBA
Hsin-Hsiung Huang (University of Central Florida)
4:00 PM in SEO 636

Algebraic Geometry Seminar
Tropical Independence and the Maximal Rank Conjecture for Quadrics
David Jensen (University of Kentucky)
4:00 PM in SEO 427
The maximal rank conjecture, which has roots in the work of Noether and Severi in the late 19th and early 20th centuries, predicts the Hilbert function of the general embedding of a general curve. In recent joint work with Sam Payne, we show that this conjecture holds for the Hilbert function evaluated at $m=2$, meaning that such a curve is contained in the expected number of independent quadrics. From this we deduce that the general curve of genus $g$ and degree $d$ in projective space of dimension r is projectively normal if and only if $(r+2)(r+1)/2$ is at least $2d-g+1$. Our proof uses techniques from tropical and nonarchimedean geometry.
Thursday October 1, 2015
Quantum Topology / Hopf Algebra Seminar
Geometry of some unitary Riemann surface braid group representations and Laughlin-type wave functions.
Mauro Spera (Dipartimento di Matematica e Fisica "Niccolo' Tartaglia" Universita' Cattolica del Sacro Cuore, Bres)
3:00 PM in SEO 612
In this talk a construction of the simplest unitary Riemann surface braid group representations is outlined via stable holomorphic vector bundles over complex tori and the prime form on Riemann surfaces. Generalised Laughlin wave functions are then introduced. The genus one case is discussed in more detail also with the help of noncommutative geometric and of Fourier-Mukai-Nahm techniques, in view of elucidating the emergence of an intriguing Riemann surface braid group duality. The talk is based on the paper "On the geometry of some unitary Riemann surface braid group representations and Laughlin-type wave functions" J.Geom.Phys. 94 (2015),120-140.
Friday October 2, 2015
Departmental Colloquium
Mappings of complex and real analytic spaces
Dale Cutkosky (University of Missouri)
3:00 PM in SEO 636
We discuss some good properties of analytic mappings, including flatness, regularity and being locally monomial. All of these properties can be obtained locally after performing suitable sequences of local blow ups. Key notions are that of a star and the stellar vault, which were introduced by Hironaka.
Monday October 5, 2015
Analysis and Applied Mathematics Seminar
TBA
Fred Hickernell (Illinois Institute of Technology)
4:00 PM in SEO 636
Wednesday October 7, 2015
Homotopy Theory Seminar
The topological Hochschild homology of finite fields II
Tasos Moulinos (UIC)
2:00 PM in SEO 1227

Homotopy Theory Seminar
TBD
Sarah Yeakel (UIUC)
3:00 PM in SEO 1227

Statistics Seminar
Design of Dose-response Clinical Trials
Naitee Ting (Boehringer-Ingelheim Pharmaceuticals Inc.)
4:00 PM in SEO 636
In the process of drug discovery and drug development, understanding the dose-response relationship is one of the most challenging tasks. It is also critical to identify the right range of doses in early stages of clinical development so that Phase III trials can be designed to confirm these doses. Usually at the beginning of Phase II, there is not a lot of available information to help guiding the study design. At this stage, Phase II clinical studies are needed to establish proof of concept (PoC), to identify a set of potentially effective and safe doses, and to estimate dose-response relationships. Challenges in designing these studies include: selection of the dose frequency and the dose range, choice of clinical endpoints or biomarkers, and use of control(s), among others. Consequences of bad Phase II study designs may lead to the delay of the entire clinical development program or the waste of R&D investment. Misleading results obtained from poor designs could cause a Phase III program to confirm a wrong set of doses, or to stop developing a potentially useful drug. Therefore, it is critical to consider an entire drug development plan, to make best use of all the available information, and to include all relevant experts in designing Phase II dose response clinical trials. This presentation discusses some of these considerations.
Thursday October 8, 2015
Logic Seminar
TBA
4:00 PM in SEO 427
Monday October 12, 2015
Analysis and Applied Mathematics Seminar
TBA
Leonid Berlyand (Penn State)
4:00 PM in SEO 636
Tuesday October 13, 2015
Logic Seminar
TBA
Sergei Bezuglyi (University of Iowa)
4:00 PM in SEO 427
Wednesday October 14, 2015
Homotopy Theory Seminar
Rational computations of K-theory
Jānis Lazovskis (UIC)
2:00 PM in SEO 1227

Algebraic Geometry Seminar
TBA
Nicola Tarasca (University of Utah)
4:00 PM in SEO 427

Statistics Seminar
TBA
Jonathan Stallings (NCSU)
4:00 PM in SEO 636
Monday October 19, 2015
Analysis and Applied Mathematics Seminar
Semi-Analytical Time Differencing Methods for Stiff Problems
Chang-Yeol Jung (Ulsan National Institute of Science and Technology)
4:00 PM in SEO 636
A semi-analytical method is developed based on conventional integrating factor (IF) and exponential time differencing (ETD) schemes for stiff problems. The latter means that there exists a thin layer with a large variation in their solutions. The occurrence of this stiff layer is due to the multiplication of a very small parameter $\epsilon$ with the transient term of the equation. Via singular perturbation analysis, an analytic approximation of the stiff layer, which is called a corrector, is sought for and embedded into the IF and ETD methods. These new schemes are then used to approximate the non-stiff part of the solution. Since the stiff part is resolved analytically by the corrector, the new method outperforms the conventional ones in terms of accuracy. In this paper, we apply our new method for both problems of ordinary differential equations and some partial differential equations.
Tuesday October 20, 2015
Logic Seminar
TBA
Caroline Terry (UIC)
4:00 PM in SEO 427
Wednesday October 21, 2015
Homotopy Theory Seminar
Towards the K-theory of finite fields
Khashayar Sartipi (UIC)
2:00 PM in SEO 1227

Statistics Seminar
TBA
Hassan Allouba (Kent State University )
4:00 PM in SEO 636

Algebraic Geometry Seminar
TBA
Matthew Kerr (Washington University)
4:00 PM in SEO 427
Friday October 23, 2015
Departmental Colloquium
TBA
Marianna Csornyei (University of Chicago)
3:00 PM in SEO 636
Monday October 26, 2015
Analysis and Applied Mathematics Seminar
TBA
Fred Weissler (Universite de Paris Nord)
4:00 PM in SEO 636
Wednesday October 28, 2015
Statistics Seminar
TBA
Yuan Ji (NorthShore University HealthSystem Research Institute)
4:00 PM in SEO 636
Friday October 30, 2015
Departmental Colloquium
TBA
Ryan Martin (UIC)
3:00 PM in SEO 636
Monday November 2, 2015
Departmental Colloquium
Peter Semrl (University of Ljubljana, Slovenia)
3:00 PM in SEO 636
Two matrices are said to be adjacent if their difference is of rank one. Fundamental theorems of geometry of matrices proved by L.-K. Hua describe the general form of bijective maps on various spaces of matrices preserving adjacency in both directions. We will present several recent improvements of these results and some applications in mathematical physics.
Wednesday November 4, 2015
Heat equation related to random walks on graphs
Melanie Pivarski (Roosevelt University)
4:00 PM in SEO 636
Friday November 6, 2015
Departmental Colloquium
TBA
Davar Khoshnevisan (University of Utah )
3:00 PM in SEO 636
Monday November 9, 2015
Analysis and Applied Mathematics Seminar
TBA
Bing-Yu Zhang (University of Cincinnati)
4:00 PM in SEO 636
Tuesday November 10, 2015
Logic Seminar
TBA
Sherwood Hachtman (UIC)
4:00 PM in SEO 427
Wednesday November 11, 2015
Algebraic Geometry Seminar
NO SEMINAR
----------
4:00 PM in SEO 427
Thursday November 12, 2015
Algebraic Geometry Seminar
TBA
Bangere Purnaprajna (University of Kansas)
12:00 PM in SEO 427
Monday November 16, 2015
Geometry, Topology and Dynamics Seminar
A construction of limiting solutions of Hitchin's equations
Laura Fredrickson (University of Texas at Austin)
3:00 PM in SEO 636
I'll describe a construction of solutions of Hitchin's equations on a compact Riemann surface near the "ends" of the SL(n,C)-Hitchin moduli space. This construction generalizes Mazzeo-Swoboda-Weiss-Witt's construction of SL(2,C) solutions of Hitchin's equations where the Higgs field is "simple." In the generalized construction, moduli spaces of irregular connections arise. This is ongoing work.

Analysis and Applied Mathematics Seminar
TBA
Brian Seguin (Loyola University, Chicago)
4:00 PM in SEO 636
Tuesday November 17, 2015
Logic Seminar
TBA
Evgeny Gordon (Eastern Illinois University)
4:00 PM in SEO 427
Wednesday November 18, 2015
Statistics Seminar
TBA
Yi Lin (UIC)
4:00 PM in SEO 636

Algebraic Geometry Seminar
TBA
Sijong Kwak (KAIST(Korea Advanced Institute of Science and Technology) )
4:00 PM in SEO 427
Friday November 20, 2015
Departmental Colloquium
TBA
David Nicholls (UIC)
3:00 PM in SEO 636
Wednesday November 25, 2015
Algebraic Geometry Seminar
NO SEMINAR
----------
4:00 PM in SEO 427
Wednesday December 2, 2015
Statistics Seminar
TBA
Xia Chen (University of Tennessee)
4:00 PM in SEO 636
Monday February 22, 2016
Analysis and Applied Mathematics Seminar
Bitcoin Protocol: A Detailed Look
Andrew Sward (Augustana College)
4:00 PM in SEO 636
Friday February 26, 2016
Departmental Colloquium
TBA
Ingrid Daubechies (Duke University)
3:00 PM in SEO 636
Professor Daubechies is the 2015-2016 WISEST Distinguished Visiting Scholar.
Friday April 29, 2016
Departmental Colloquium
Atkin Memorial Lecture
TBA (TBA)
3:00 PM in TBA
UIC LAS MSCS seminars seminar calendar