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Codes, Sstructures, and exceptional Lie algebras
20190213

Speaker: Alberto Elduque (Univ. of Zaragoza, Spain)

Sstructures on Lie algebras have been defined recently by Vinberg, as an extension of gradings by abelian groups. In this talk it will be shown how the exceptional simple Lie algebras of types E7 and E8are endowed with some SL2nstructures, and are thus described very nicely in terms of the...



Abstract Algebraic Representation
20180926

Speaker: Jaroslav Nesetril (Charles Univ., Prague, Czech Republic)

Representing posets, groups, monoids and categories by other structures is associated with Prague school of categories. In this lecture we survey recent development which puts this classical topic in a yet another (combinatorial and model theoretic) context. There will be coffee and cookies...



Kepler's problem and spaces of constant curvature
20180620

Speaker: Velimir Jurdjevic (Univ. Toronto, Canada)

Kepler's problem (around 1706) concerns the motion of a planet around an immovable planet in the presence of the gravitational force. Based on empirical evidence, Kepler stated that the moon moves on an elliptical path around the earth (known as Kepler's first law, and secondly he stated that the...



From oscillations to integrable systems and Symplectic Geometry
20180502

Speaker: JeanPierre Françoise (Sorbonne Univ., Paris, France)

Oscillations can be observed in many natural physical and biological phenomena. The pendulum can be used as an introduction to several mathematical concepts. Actually Jacobi created the theory of elliptic functions to solve the motion of the pendulum. His work can be revisited using symplectic...



Wow, so many minimal surfaces!
20180321

Speaker: André Neves (Univ. of Chicago, USA)

Minimal surfaces are ubiquitous in geometry and applied science but their existence theory is rather mysterious. For instance, Yau in 1982 conjectured that any 3manifold admits infinitely many closed minimal surfaces but the best one knows is the existence of at least three.After a brief...



On dimensionality and functional data analysis
20180228

Speaker: Philippe Vieu (Univ. Paul Sabatier, Toulouse, France)

The talk will be on statistical modelling for problems involving functional data. Functional data are elements of infinite dimensional spaces, and their statistical analysis has been popularized in the last twenty years (mainly with RamsaySilverman's books, [9]), leading to a new field of...



The mathematics of liquid crystals
20180214

Speaker: John M. Ball (Univ. of Oxford, UK)

The understanding of liquid crystal behaviour has traditionally been an area with a fertile interaction between science and mathematics. The lecture will describe different theories of liquid crystals and some recent results concerning their predictions and the connection between them....



Três bolas matemáticas
20170927

Speaker: Étienne Ghys (ENSLyon, France)

This colloquium lecture is part of the Pedro Nunes Lectures 2017, organized by SPM and CIM, and sponsored by Fundação Calouste Gulbenkian. ...



The interaction of a gap with a free boundary in a twodimensional dimer system
20170607

Speaker: Christian Krattenthaler (Univ. Vienna, Austria)

I shall consider a rhombus tiling model (equivalently, a dimer model on a hexagonal graph) with a free boundary. The correlation of a small triangular hole in this model will be determined. As I shall explain, this kind of problem features phenomena which are parallel to phenomena in...



Leftorderability of 3manifold groups
20170503

Speaker: Cameron Gordon (University of Texas at Austin, USA)

The fundamental group is a more or less complete invariant of a 3dimensional manifold. We will discuss how the purely algebraic property of this group being leftorderable is related to two other aspects of 3dimensional topology, one geometric and the other essentially analytic....



Computational modelling of problems of solid deformation, with applications of goal oriented techniques to thermoforming processes
20170406

Speaker: John Whiteman (Brunel Univ. London, UK)

The reliability of computational models of physical processes has received much attention and involves issues such as validation of the mathematical models being used, the error in any data that the models need and the accuracy of the numerical schemes being used, verification. These issues are...



Leibniz is still alive  and so are his mathematical ideas in the third millennium
20160921

Speaker: Marcel Erné (Leibniz Universität Hannover, Germany)

In the current year 2016, we are celebrating the third centennial of Leibniz's death. This is a good occasion to present some highlights in the immense mathematical work of the great universal genius under a modern point of view, and to add some surprising interpretations that might have elapsed the...



(Higher) representation theory
20160622

Speaker: Volodymyr Mazorchuk (Univ. Uppsala, Sweden)

In this talk I want to present my point of view on what (higher) representation theory is and why it is useful. I would like to show, using a baby example, how classical representation theory transforms into higher representation theory, in particular, explaining what the latter one is. At the end,...



L'art et la mathématique
20151111

Speaker: Cédric Villani (Institut Henri Poincaré, Paris, France)

O vídeo da conferência pode ser visto aqui. Resumo: "Ninguém pode ser Matemático se não tiver a alma de um poeta", dizia Sonia Kovalevskaya. No entanto, a lógica matemática dificilmente parece deixar lugar à intuição,...



Normal forms in differential geometry and metrics on Lie groupoids
20150609

Speaker: Rui Loja Fernandes (Univ. of Illinois at UrbanaChampaign, USA)

In this lecture I will recall some classical and not so classical normal form theorems in differential geometry and I will explain a new, far reaching, metric approach to these results using the language of Lie groupoids....



The sensitivity of interest rate options to monetary policy decisions: a regimeshift pricing approach
20150520

Speaker: René Ferland (Université du Québec à Montréal, Canada)

We look at whether monetary decisions constitute a significant macrofinance risk for interest rate options and related implied volatilities. We devise an optionpricing model based on the dynamics of the Federal Reserve’s target rate via a regimeshift approach modeled as discrete Markov...



The random graph
20140717

Speaker: Peter Cameron (Queen Mary, Univ. London, UK)

In 1963, Erdos and Rényi proved the paradoxical result that there is a graph R with the property that, if a countable graph is chosen by selecting edges independently with probability 1/2, the resulting graph is almost surely isomorphic to R. Their proof was a beautiful example of a...



Pentagram Map, twenty years after
20140212

Speaker: Sergei Tabachnikov (Pennsylvania State Univ., USA)

Introduced by R. Schwartz more than 20 years ago, the pentagram map acts on plane ngons, considered up to projective equivalence, by drawing the diagonals that connect secondnearest vertices and taking the new ngon formed by their intersections. The pentagram map is a discrete completely...



Univalent Foundations of Mathematics
20130725

Speaker: Vladimir Voevodsky (Institute for Advanced Study, Princeton, USA)

I will outline the main ideas of the new approach to foundations of practical mathematics which we call univalent foundations. Mathematical objects and their equivalences form sets, groupoids or higher groupoids. According to Grothendieck's idea higher groupoids are the same as homotopy types....



Robust optimization: the need, the challenge, the success
20130703

Speaker: Aharon BenTal (TechnionIsrael Institute of Technology, Israel)

We list and illustrate by examples various sources of uncertainty associated with optimization problems. We then explain the difficulties arising when solving such uncertainty affected problems due to lack of full information on the nature of the uncertainty on one hand, and the likelihood of facing...



Minimizing greenhouse emissions in vehicle routing
20130228

Speaker: Gilbert Laporte (HEC, Montréal, Canada)

The Vehicle Routing Problem holds a central place in distribution management. In the classical version of the problem the aim is to distribute goods to a set of geographically dispersed customers under a cost minimization objective and various side constraints. In recent years a number of...



Variations on a conjecture of Nagata
20120328

Speaker: Ciro Ciliberto (Univ. degli Studi di Roma Tor Vergata, Italy)

The classical multivariate Hermite interpolation problem asks for the determination of the dimension of the vector space of polynomials of a given degree d in a given number r of variables having n assigned, sufficiently general, zeroes with given multiplicities. This is trivial for n=1, but quite...



From Numerics to Computational Science and Engineering
20111207

Speaker: Rolf Jeltsch (ETH Zurich, Switzerland)

The birth of the discipline numerics is due to the invention of modern computers in the forties of the last century. The main task was to learn to live with the deficiencies of computers, which are the limited memory space, that only a finite number of arithmetical operations can be carried out and...



Counting sheaves on curves
20110609

Speaker: Raul Pandharipande (Princeton/IST)

I will explain the counting of stable pairs on algebraic curves and the interactions with singularities, Hilbert schemes, and knots....



Chebfun: a new kind of numerical computing
20110413

Speaker: Lloyd N. Trefethen (Univ. Oxford, UK)

For a long time there have been two kinds of mathematical computation: symbolic and numerical. Symbolic computing manipulates algebraic expressions exactly, but it is unworkable for many applications since the space and time requirements tend to grow combinatorially. Numerical computing avoids the...



KazhdanLusztig polynomials in algebra, geometry, and combinatorics
20110127

Speaker: Francesco Brenti (Univ. of Roma "Tor Vergata", Italy)

In this talk I will define the KazhdanLusztig polynomials, and then I will survey the results on, and the applications of, these polynomials to algebra, geometry, and combinatorics....



Point source discovery in complicated domains
20101124

Speaker: Richard Tsai (Univ. Texas at Austin, USA)

We consider the inverse problem of discovering the location of point sources from very sparse point measurements in a bounded domain that contains impenetrable obstacles. The sources spread according to a class of linear equations, including the Laplace, heat, and Helmholtz equations, and limited...



Four colours suffice
20100707

Speaker: Robin J. Wilson (Open Univ. and Oxford Univ., UK)

TBA...



Counting the rational numbers
20100618

Speaker: Herbert S. Wilf (Univ. Pennsylvania, USA)

We describe a new method of enumerating the rational numbers, based on a certain tree at each of whose nodes a fraction lives....



Multiscale discretizations for flow, transport and mechanics in porous media
20100608

Speaker: Mary Fanett Wheeler (Univ. of Texas at Austin, USA)

A fundamental difficulty in understanding and predicting largescale fluid movements in porous media is that these movements depend upon phenomena occuring on small scales in space and/or time. The differences in scale can be staggering. Aquifers and reservoirs extend for thousands of meters, while...



Interpolation in several variables
20100210

Speaker: Alain Lascoux (Univ. ParisEst, France)

Compared to the case of functions of one variable, or to the case of symmetric functions, there are not many algebraic tools to manipulate polynomials in several variables. The symmetric group can greatly help in that matter. Newton found how to transform a discrete set of data into an algebraic...



Computational Multiscale Modeling
20091104

Speaker: Bjorn Engquist (Univ. Texas at Austin, USA)

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New results on the trading rule "Buy and Hold"
20090930

Speaker: Albert Shiryaev (Steklov Mathematical Institute, Moscow, Russia)

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TBA
20090903

Speaker: Omar Ghattas (Univ. Texas at Austin, USA)

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The Memoirs of Évariste Galois
20090713

Speaker: Peter M. Neumann (Univ. Oxford, UK)

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Calculus of operator functions
20090615

Speaker: Rajendra Bhatia (Indian Statistical Institute, New Delhi, India)

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Exploring the Fourth Dimension: "Flatland: the Movie" and the geometric art of Salvador Dali and Ramon Lull
20090429

Speaker: Thomas Banchoff (Brown Univ., USA)

In the new movie version of "Flatland", the central geometric figure in that film is a cube that rotates about its center in threespace producing a number of central slices in the plane including a square, a rectangle, a rhombus, and a hexagon. What are the analogous central hyperplane...



Was Cantor Surprised?
20090304

Speaker: Fernando Gouvêa (Colby College, Maine, USA)

A wellknown story tells that Cantor was so surprised by one of his theorems that he exclaimed "I see it, but I don't believe it!" We will examine the sources to see what really happened. ...



Alternating sign matrices: at the crossroads of algebra, combinatorics and physics
20080926

Speaker: Xavier Viennot (LaBRI, CNRS and Univ. Bordeaux 1, France)

Alternating sign matrices have been introduced by combinatorists in the 80's as an extension of the notion of permutation matrices. A simple formula for the number of such matrices of size n has been conjectured. The resolution of this conjecture has been a very active subject in the 80's and 90's....



Compressive Sampling
20080626

Speaker: Emmanuel J. Candes (Caltech, USA)

One of the central tenets of signal processing is the Shannon/Nyquist sampling theory: the number of samples needed to
reconstruct a signal without error is dictated by its bandwidththe length of the shortest interval which contains the support of the spectrum of the signal under study. Very...



On the geometry of interest rate models
20080507

Speaker: Tomas Björk (Stockholm School of Economics, Sweden)

The purpose of this talk is to give an overview of some recent work concerning the structural and geometric properties of the
evolution of the forward rate curve in an arbitrage free bond market. The main problems to be discussed are as follows.
1. When is a given forward rate model consistent...



The uses of mathematical images in the seventeenth century, from Galileo to Newton
20080313

Speaker: Jean Dhombres (CNRS, EHESS, Paris)

From long ago, historians have shown the importance of images (emblems books, jesuit propaganda, etc.) during the seventeenth century. Historians of science also emphasized the role played by Optics and its representations. But there has been quite an absence about the role played by images as well...



Flow control in the presence of shocks
20071213

Speaker: Enrique Zuazua (IMDEAMatemáticas & Universidad Autónoma de Madrid, Spain)

Flow control is one of the most challenging and relevant topics connecting the theory of
Partial Differential Equations (PDE) and Control Theory. On one hand the number of
possible applications is huge including optimal shape design in aeronautics. On the other
hand, from a purely mathematical...



What's an infinite dimensional manifold and how can it be useful in anatomy?
20070919

Speaker: David Mumford (Division of Applied Mathematics, Brown University, USA)

There has been a huge explosion in medical
imaging, in spatial and temporal resolution, in imaging many processes as well as organs.
New mathematical tools have entered the game, which are not so elementary. It's important to have some basic understanding of them, to know how what to expect of...



Singular perturbation systems related to segregation
20070725

Speaker: Luis Caffarelli
(University of Texas at Austin, USA)

I will discuss a singular perturbation system related to segregation and the regularity properties of the limiting solution and its free boundaries.
Area(s): ...



What geometry in the early history of architecture?
20061017

Speaker: Kim Williams

It is commonly said that Euclidean geometry played a large part in the development of architecture, but is this really true? An examination of the two earliest and best known treatises of architecture, On architecture by Vitruvius and the Sketchbooks of Villard de Honnecourt reveal no trace of...



Variational Analysis and Generalized Differentiation: New Trends and Developments
20060705

Speaker: Boris Mordukhovich
(Dep. Mathematics, Wayne State Univ.)

Nonsmooth functions, sets with nonsmooth boundaries, and setvalued mappings naturally and frequently appear in various aspects of analysis. Constrained optimization, calculus of variations and its modern form of optimal control, stochastic and statistical problems, mathematical economics, etc., are...



Homomorphisms of the alternating group A_5 into semisimple groups
20060627

Speaker: George Lusztig (Dept. Math., MIT)

Usually in representation theory one studies homomorphisms of a complicated group G into a simpler group: the general linear group of a vector space. But it is also interesting to replace the general linear group by other algebraic groups such as
symplectic, orthogonal or even exceptional groups....



Mathematical models for cell motion
20060530

Speaker: Benoit Perthame
(??cole Normale Supérieure, Paris)

Several transportdiffusion systems arise as simple models in chemotaxis (motion of bacterias or amebia interacting through a chemical signal) and in angiogenesis (development of capillary blood vessels
from an exhogeneous chemoattractive signal by solid tumors). These systems describe the...



Neuronal Calcium Signaling
20060404

Speaker: Steve Cox (Computational and Applied Math., Rice University)

Calcium, the most important of the second messengers, regulates the synaptic plasticity that is underlies our ability to learn. Calcium enters cells through singleprotein channels in the cells' outer membrane. We exploit the ability to dynamically monitor
cytosolic calcium, throughout `intact'...



Lorenz Strange Atractors
20060214

Speaker: Marcelo Viana (IMPA, Brasil)

The Lorenz strange attractor, introduced in the sixties in the context of thermal convection and weather prediction, became a
paradigm chaotic behavior, and a crucial model to try and describe this type of dynamics.
In the nineties there were two fundamental developments:
On the one hand,...



The Poincare Conjecture and Algorithmic Problems in Algebra
20050912

Speaker: Alexey Sossinsky (Indep. Univ. Moscow)

It has been announced that the Poincare
Conjecture (claiming that any simply connected closed compact threedimensional manifold is homeomorphic to the sphere), one of the most famous problems in mathematics,
has been solved by Grisha Perelman of St.Petersburg.
Although no complete verifiable...



Color printers, mailboxes, fish, and Homer Simpson  or  Centroidal Voronoi tessellations: algorithms and applications
20050725

Speaker: M. D. Gunzburger (Florida State Univ.)

One of the beauties of mathematics is that it can uncover connections between seemingly disparate applications. One of the most fertile grounds for unearthing connections is computational algorithms where one often discovers that an algorithm developed for one application is equally useful in...


