## Programs & Events

##### Special Colloquium: "Spheres"

Apr 5, 2012

A historical survey on progress in understanding topological spheres and differentiable spheres.

Thursday, April 5, 2012 from 4:00pm-5:00pm. There will be a reception following the talk.

##### Global Arithmetic Dynamics

Mar 19 - 23, 2012

This workshop will examine global arithmetic dynamics from the perspectives of number theory, algebraic geometry, and model theory. It will introduce aspects of this topic to a larger audience, and clarify connections between different perspectives. In addition, there will be extensive discussion periods in which participants can collaborate on theoretical and computational aspects of the topic.

##### Organizing Committee

- Xander Faber
- Michelle Manes
- Lucien Szpiro
- Thomas Tucker
- Michael Zieve

##### Complex and p-adic Dynamics

Feb 13 - 17, 2012

This workshop will bring together researchers working in classical complex dynamics and in the newer area of p-adic (nonarchimedean) dynamics. It will promote interactions between the two groups by highlighting the similarities and differences between complex and p-adic dynamics.

In particular, it will address Berkovich space, whose introduction has greatly enhanced the exchange of ideas between complex and p-adic dynamics.

##### Organizing Committee

- Matthew Baker
- Rob Benedetto
- Charles Favre
- Kevin Pilgrim
- Juan Rivera-Letelier

##### Complex and Arithmetic Dynamics

Jan 30 - May 4, 2012

The goal of this program is to bring together researchers in complex dynamics, arithmetic dynamics, and related fields, with the purpose of stimulating interactions, promoting collaborations, making progress on fundamental problems, and developing theoretical and computational foundations on which future work will build. Complex dynamics is the study of iteration of holomorphic self-maps of a complex space. Fundamental examples of such maps arise as algebraic self-maps of algebraic varieties. Starting with the fundamental results of Fatou and Julia, complex dynamics has evolved into a well established field with many deep theorems and many important unresolved questions. Arithmetic dynamics refers to the study of number theoretic phenomena arising in dynamical systems on algebraic varieties. Many global problems in arithmetic dynamics are analogues of classical problems in the theory of Diophantine equations or arithmetic geometry, including for example uniform bounds for rational... (more)

##### Organizing Committee

- Rob Benedetto
- Laura DeMarco
- Mikhail Lyubich
- Juan Rivera-Letelier
- Joseph Silverman
- Lucien Szpiro
- Michael Zieve

##### Mathematical and Statistical Aspects of Cryptography (in Kolkata, India)

Jan 12 - 14, 2012

This workshop focuses on mathematical and statistical aspects of public key cryptography. The main ingredients from mathematics so far include discrete logarithms and factoring over the integers, generalizations of the discrete logarithm to elliptic curves, hyperelliptic curves and further generalizations, aspects of infinite non-abelian groups, and closest vector problems (CVP) in integer lattices. Cryptanalysis in all of these areas can involve analyses of patterns in vast amounts of data, hence the need for statistical methods. One goal of this workshop, though not the only one, is to focus attention on the problem of quantifying the complexity of lattice-based problems, for example extrapolating the difficulty of solving a CVP in an integer lattice as a function of its dimension and other parameters.

*A copy of the presentations given at this workshop is available as a PDF... (more)*

##### Organizing Committee

- Jeffrey Hoffstein
- Jill Pipher
- Bimal Roy

##### Synchronization-reducing and Communication-reducing Algorithms and Programming Models for Large-scale Simulations

Jan 9 - 13, 2012

As concurrency in scientific computing pushes beyond a million threads and performance of individual threads becomes less reliable for hardware-related reasons, attention of mathematicians, computer scientists, and supercomputer users and suppliers inevitably focuses on reducing communication and synchronization bottlenecks. Though convenient for succinctness, reproducibility, and stability, instruction ordering in contemporary codes is commonly overspecified. This workshop attempts to outline evolution of simulation codes from today's infra-petascale to the ultra-exascale and to encourage importation of ideas from other areas of computer science into numerical algorithms, new invention, and programming model generalization.

##### Organizing Committee

- David Keyes
- Matt Knepley
- Katherine Yelick

##### Boltzmann Models in Kinetic Theory

Nov 7 - 11, 2011

The celebrated Boltzmann equation is the foundation of the kinetic theory for dilute collections of particles, which undergo elastic binary collisions. The Boltzmann theory is at the center of a series of multi-scaled physical models that connect microscopic multiparticle models to macroscopic fluid models such as the Navier-Stokes equations:

*Particles → Boltzmann → Fluids*

The first arrow refers the Boltzmann-Grad limit, while the second arrow refers to various hydrodynamic limits which lead to the fundamental equations of fluids. The Boltzmann theory therefore provides a practical tool and machinery for deriving macroscopic models in broad physical applications. Due to its importance, there has been an explosion of mathematical studies, both theoretical and numerical, for the Boltzmann equation.A major open problem that remains is to determine whether or not smooth initial data would lead to a unique global-in-time solution of the Boltzmann... (more)

##### Organizing Committee

- Kazuo Aoki
- Yan Guo
- Shi Jin
- Lorenzo Pareschi
- Laure Saint-Raymond

##### NSF Mathematics Institutes Modern Math Workshop (at SACNAS)

Oct 26 - 27, 2011

The eight NSF mathematics institutes are pleased to offer three concurrent sessions immediately preceding the SACNAS annual meeting â€“ one for graduate students and recent PhDs, and two for undergraduate students â€“ to invigorate the research careers of minority mathematicians and mathematics faculty at minority-serving institutions. The â€œModern Math Workshopâ€ will highlight presentations on topics drawn from the institutesâ€™ upcoming programs, a keynote speaker, and an informative panel presentation on the 2012-13 programs and workshops. The two undergraduate sessions (applicants will choose one) are appropriate for students of any major interested in learning how mathematics contributes to our understanding of various scientific topics. Activities will include lectures and group work.

All sessions will begin with lunch on Wed. Oct. 26 and include an evening reception. The sessions will continue on Thursday morning and will end at 12:30 pm prior to the SACNAS conference lunch.... (more)

##### Novel Applications of Kinetic Theory and Computations

Oct 17 - 21, 2011

There are several fundamental applications involving kinetic theory and computations. They range from semiconductor modeling involving kinetic and quantum charged transport, radiative transfer in cosmology, conservative and dissipative phenomena in rarefied gas dynamics in mixtures, and grain and polymer flows.

Issues to be addressed involve the derivation and multi-scale modeling due to different scales of effective constants, spatial heterogeneities and strength of boundary conditions. Because the basic drift-diffusion, hydrodynamic and quantum models may interact through interfaces, a basic understanding of boundary conditions as well as phase transitions are critical. An example of such modeling problem appears naturally in semiconductors devices where the electron and holes density flows through a highly heterogeneous crystal lattice.

It is well established that drift-diffusion models are currently inadequate for the simulations of submicron devices where effective fields... (more)

##### Organizing Committee

- Irene Gamba
- Axel Klar
- Benoit Perthame
- Christian Ringhofer
- Chi-Wang Shu

##### Vlasov Models in Kinetic Theory

Sep 19 - 23, 2011

Vlasov-type models deal with continua of particles where the electric charges dominate the collisions, so that the collisions are ignored. They occur in physical plasmas, including astrophysical plasmas and fusion reactors.

There are many examples of astrophysical plasmas of this type, such as the solar wind. When a fusion reactor is very hot, the relevant times scales are so short that collisions can be ignored. Vlasov theory also models systems where the dominant force is gravity, such as clusters of stars or galaxies.

##### Organizing Committee

- Pierre Degond
- Francis Filbet
- Robert Glassey
- Jingmei Qiu
- Gerhard Rein

##### AWM Anniversary Conference at Brown University

Sep 17 - 18, 2011

40 Years and Counting: 2011 is the 40th anniversary of the Association for Women in Mathematics (AWM). With this conference, AWM continues to celebrate the progress of women in mathematical professions and to recognize individual achievements. Join us this fall on the Brown University campus in historic Providence, RI.

##### Organizing Committee

- Georgia Benkart
- Kristin Lauter
- Jill Pipher

##### Kinetic Theory and Computation

Sep 7 - Dec 9, 2011

Kinetic theory plays a central role in many areas of mathematical physics, from nanoscales to continuum mechanics. It is an indispensable tool in the mathematical description of applications in physical and social sciences, from its origin in dilute gases, to wide applications such as semi-conductors, polymers, cells, plasma, galaxies, traffic networking, and swarming. The number of particles is typically more than 10^{20}.

On the one hand, kinetic models provide more detailed and accurate description of regimes where hydrodynamic equations are either invalid or simply not available. On the other hand, because modern computers are still inadequate in simulating the molecular or even quantum dynamics in emerging industrial needs in micro- and nanotechnology, kinetic equations provide models that can capture important features of microscopic or quantum phenomena with a manageable computational cost. Kinetic theory is at the core of multiscale modeling, which connects fundamental... (more)

##### Organizing Committee

- Jose Blanchet
- Francis Filbet
- Irene Gamba
- Yan Guo
- Chi-Wang Shu
- Walter Strauss