# News 2010

• November, 2010

### Conference in Memory of Professor Leon Ehrenpreis

A two-day conference in memory of Professor Leon Ehrenpreis was held November 15 and 16, 2010. Speakers: C. Epstein (University of Pennsylvania), J. E. Fornaess (University of Michigan), C. Gutierrez (Temple University), X. Huang (Rutgers University), H. Iwaniec (Rutgers University), J. J. Kohn (Princeton University), I. Rivin (Temple University), P. Sarnak (Institute for Advanced Study), E. Stein (Princeton University), F. Treves (Rutgers University). A memorial banquet was also held, where Professor Ehrenpreis' colleagues and friends shared fond memories. Present throughout the conference was Mrs. Ahava Ehrenpreis, who also spoke at the memorial banquet. Also present for the conference and banquet were several of Professor Ehrenpreis' children and grandchildren. The conference was organized by Temple mathematics department members Shiferaw Berhanu, Marvin Knopp, Edward Letzter, and Gerardo Mendoza.

• October, 2010

### Professor John Paulos in national media.

John Paulos' commentary appeared three times in the national media this month: New York Times, Washington Post, and ABC News.

• September, 2010

### Benjamin Seibold in local, national, and international media for traffic research

Assistant Professor Benjamin Seibold was featured in several media outlets for his research on traffic modeling, including: The New York Times, The Wall Street Journal Journal, The Financial Times (London), KYW Newsradio, NBC Philadelphia, The Philadelphia Inquirer, and News 1130 (Vancouver, Canada). Temple converage included Temple News here and here. The articles concern his research on phantom traffic jams.'' To quote from the New York Times piece (appearing under his own byline): "These so-called 'phantom traffic jams' can happen without any obstacles on the road. Instead they are a property of the flow. Traffic models and simulations show that once traffic volume exceeds a critical threshold, small perturbations in the flow amplify, and traffic waves develop. These traffic waves, so called 'jamitons,' can travel backward along the road, forcing drivers to brake and accelerate constantly." And: "Our research group, consisting of researchers in the United States, Canada, and Saudi-Arabia, has found that jamitons behave much like detonation waves. Using theories that were originally developed to study explosions, fundamental properties of traffic waves can be explained and predicted."

• August, 2010

Assistant Professor David Futer has been awarded a new NSF research grant, Hyperbolic geometry of knots and 3-manifolds, for $112,096. From the absract: "A 3-manifold is a space where an object such as a helicopter can move around in three distinct perpendicular directions. The universe that we inhabit is a 3-manifold whose global geometry we do not yet understand. Another rich source of examples comes from the spaces that surround different knots. Powerful theorems of Thurston, Perelman, and Mostow imply that almost every knot complement, and more generally almost every 3-manifold, has a unique hyperbolic metric. That is, there is a standard way to measure the space, so that every 2-dimensional cross-section curves like a saddle. At the moment, while we know that this standard hyperbolic metric exists, very little is known about how to relate it to easily computable quantities such as the complexity of a knot diagram. The main goal of this project is to make these relations much more concrete." • August, 2010 ### Benjamin Seibold awarded new NSF grant Assistant Professor Benjamin Seibold has been awarded a new NSF research grant, Phantom traffic jams, continuum modeling, and connections with detonation wave theory. From the abstract: "A 'phantom' traffic jam is a small congestion in vehicular traffic that occurs spontaneously, in the absence of bottlenecks, obstacles, or any discernible causes on the road. Observations show that uniform traffic flow can develop inhomogeneities, which turn into traveling traffic jams. These traffic jam waves ('jamitons') enforce unexpected braking maneuvers, and thus impose stress on drivers and materials, waste fuel and increase pollution, and are hot spots for potential vehicle collisions. In this project, the behavior of phantom traffic jams and jamitons is studied. Theoretical analogies between traffic modeling and gas dynamics, hydraulics, and astrophysics, are established and used to advance the understanding of traffic flow. These connections yield insight into the situations under which phantom traffic jams can occur, and allow the prediction of the shape and velocity of the resulting jamitons. A fundamental understanding of phantom traffic jams is a key step in devising appropriate countermeasures to avoid or ameliorate them. The development of effective ways to manage or prevent phantom traffic jams could have a considerable impact on the reduction of fuel consumption and pollution. Two possible strategies that will be incorporated into the models and investigated are: assisted driving devices in the individual vehicles, and adaptively controlled speed limits on highways. A crucial component of this study is the interplay between theoretical analysis and numerical experiments. The research in this project involves three international collaborations, as well as graduate and undergraduate research projects." • August, 2010 ### Professor Leon Ehrenpreis, 1930-2010. With great sadness we report the passing of Professor Leon Ehrenpreis. Professor Ehrenpreis, an internationally renowned mathematician and scholar, had been a member of the Temple University Department of Mathematics since 1984. Before joining Temple he was a professor at NYU's Courant Institute of Mathematical Sciences and at Yeshiva University. He also held positions at Brandeis University and the Institute for Advanced Study. Among his significant contributions to mathematics was the Malgrange-Ehrenpreis Theorem. Update: Obituaries for Professor Ehrenpreis appeared in The Philadelphia Inquirer, The Philadelphia Daily News, and The Temple News. • August, 2010 ### Yury Grabovsky awarded new NSF grant Yury Grabovsky has been awarded a new NSF grant, Stability and macroscopic properties of heterogeneous media, for$102,641. From the abstract: "The investigator studies problems related to composite materials, martensitic phase transformations, and morphological stability in materials. First, he considers exact relations and links for effective tensors of fiber-reinforced elastic composites, by applying the general theory developed by him and his collaborators. The general theory provides a strategy for finding every relation and link. However, the actual execution of that strategy is far from trivial. The case of fiber-reinforced elastic composites is both important for applications and incredibly challenging technically, because the microstructure is two-dimensional while the properties of the composite are represented by three-dimensional fully anisotropic elastic tensors. This topic builds on the successful solution of a similar, simpler problem in the context of Hall-effect conductivity. A second problem concerns morphological stability of phase boundaries in materials capable of undergoing martensitic phase transformations." Also: "Heterogeneous media, or media with internal structure, are of great importance in applications. Composite materials, which have by now become ubiquitous, are one example. Another example is shape memory alloys and other smart materials."

• August, 2010

Edward Letzter was co-organizer, together with Toby Stafford (Manchester), James Zhang (U. Washington), Pere Arra (Barcelona), Ken Brown (Glasgow), Steven O'Hagan (Glasgow) and Tom Lenagan (Edinburgh) of New Trends in Noncommutative Algebra: A Conference in Honor of Ken Goodearl's 65th Birthday. The conference took place August 9-13. Letzter is co-PI on an NSF grant for $35,000 that provided partial funding for the conference. • July, 2010 ### New Faculty Member: Vasily Dolgushev Dr. Vasily Dolgushev joined our department as an Associate Professor in July. Dr. Dolgushev received his Ph.D. in mathematics from M.I.T. in 2005, and his Ph.D. in theoretical physics from the Joint Institute for Nuclear Research (Dubna, Russia) in 2003. He was a postdoc at Northwestern University, and until coming to Temple he was an assistant professor at University of California, Riverside. His research interests are in noncommutative geometry, homological algebra, category theory and mathematical physics. Most of the problems he is working on are motivated by questions in mathematical physics. The approaches to these problems involve elaborate techniques of higher algebraic structures such as homotopy algebras, higher operads, and higher categories. The solutions of these problems are also applied to questions in Lie theory, algebraic geometry, and algebraic topology. Dr. Dolgushev's research is funded by the NSF. • July, 2010 ### New Faculty Member: Prince Chidyagwai Dr. Prince Chidyagwai joined our department in July as a postdoctoral research assistant professor. Dr. Chidyagwai received his Ph.D. in computational and applied mathematics from Rice University in 2010. Dr. Chidyagwai's research interests are in numerical methods for partial differential equations, in particular: discontinuous Galerkin methods, flow and transport in porous media, and multi-numerics approaches for solving coupled multi-physics problems. • June, 2010 ### Visiting Fulbright Scholar: Lahcen Laayouni Dr. Lahcen Laayouni, of the School of Science and Engineering, Al Akhawayn University, Morocco, is a Fulbright Scholar visiting our department during June, July, and August. He is collaborating with Daniel Szyld. • May, 2010 ### Shiferaw Berhanu co-organizer of Marrakesh Workshop Shiferaw Berhanu was co-organizer, together with Moulay Youssef Barkatou (Poitiers), Abdelhamid Meziani (Florida International), Rafik Meziani (Kenitra), and Nordine Mir (Rouen) of the Marrakesh Workshop Geometric Analysis of Several Complex Variables and its interactions, May 10-14, 2010. • May, 2010 ### Igor Rivin named member of IAS for 2010-2011 Igor Rivin has been named a visiting member of the Institute for Advanced Study, Princeton, New Jersey, for the 2010-2011 academic year. He will be on leave from Temple during this time. • May, 2010 ### Gerardo Mendoza co-organizer of AIMS special session Gerardo Mendoza was co-organizer, with Michael Ruzhansky and B.-Wolfgang Schulze, of the special session Geometric and Singular Analysis, at the 8th American Institute of Mathematical Sciences Conference on Dynamical Systems, Differential Equations and Applications, May 25-28, in Dresden, Germany. • May, 2010 ### Yury Grabovsky co-organizer of SIAM minisymposium Yury Grabovsky and Lev Truskinovsky co-organized the minisymposium, Instabilities and Micro-structures in Non-linear Elasticity at the May 23-26 SIAM Conference on Mathematical Aspects of Materials Science. • May, 2010 ### Henok Mawi fellow at MSRI Henok Mawi was invited to spend the Spring 2011 semester as a fellow at the Mathematical Sciences Research Institute, participating in the program Free Boundary Problems, Theory and Applications. • May, 2010 ### John Paulos article in Sunday New York Times Magazine John Paulos published his article, Metric Mania in the Sunday New York Times Magazine. • April, 2010 ### Henok Mawi defends Ph.D. dissertation Henok Mawi successfully defended his dissertaion, The refractor problem with loss of energy and Monge-Ampere type equations. Cristian Gutierrez was his thesis advisor. • April, 2010 ### Igor Rivin co-PI on new NSF grant An NSF grant has been awarded to Jie Wu (PI), Yuan Shi (co-PI), Saroj Biswas (co-PI), Igor Rivin (co-PI), and Michael Klein (co-PI), Acquisition: A Hybrid High-Performance GPU/CPU System, for$839,221. From the abstract: "This project, acquiring a hybrid high-performance GPU (graphics processing unit)/CPU system, enables broader heterogeneous computing by deploying multiple types of computing nodes and allowing each to perform the tasks to which it is best suited in traditional CPU-based, GPU based, and hybrid GPU/CPU applications."

• April, 2010

### Shiferaw Berhanu awarded new NSF grant

Shiferaw Berhanu has received a new grant from the National Science Foundation, Semilinear and nonlinear pdes motivated by complex variables and CR manifolds and the Bochner extension phenomenon, for $134,705. From the abstract: "The research in this project is expected to have applications to partial differential equations and geometry. The semilinear equations arise from a geometrical problem that concerns the existence of nontrivial infinitesimal bendings for a given surface. This problem has physical applications to the elasticity of thin shells. The nonlinear equations arise in numerous geometrical and physical applications including in the modeling of atmospheric phenomena, and in the study of limit shapes of surfaces that minimize surface tension." • April, 2010 #### Grosswald Lectures 2010: Andrei Okounkov, Princeton University (Fields Medal 2006): From the longest increasing subsequence to instanton counting, April 20, 21, and 22. • April, 2010 ### John Paulos article in New York Review of Books John Allen Paulos published a review of the Grigory Perelman biography "Perfect Rigor: A Genius and the Mathematical Breakthrough of the Century" in the April 29, 2010 edition of the New York Review of Books. • April, 2010 ### Edward Letzter awarded NSA grant Edward Letzter has received a grant from the National Security Agency for his project "Complete Noncommutative Algebras." The award provides$65,000 for a two-year period and will focus on "the structure of certain natural, noncommutative analogues of classical, commutative, formal power series rings. Noncommutative power series expansions arise in mathematical physics, noncommutative geometry, combinatorics, and number theory."

• March, 2010

### Daniel Szyld appointed to program committee

Daniel Szyld was appointed to the Program Committee of the Conference on Computer Aspects of Numerical Algorithms (CANA'10), to be held is Wisla, Poland, October 18-20, 2010.

• March, 2010

### David Fritzsche defends PhD dissertation

David Fritzsche successfully defended his PhD dissertation, "Overlapping and Nonoverlapping Orderings for Preconditioning". His degreee was obtained under a joint PhD program between the Temple mathematics department and the University of Wuppertal, Germany.

• January, 2010

### Benjamin Seibold traffic modeling project

Benjamin Seibold was part of a traffic modelling project that was 39th on Discover magazine's Top 100 Stories of 2009.

• January, 2010

### Cristian Gutierrez receives NSF funding

Cristian Gutierrez has received NSF funding for his project "Nonlinear equations of Monge-Ampere type." The award provides \$200,000 for a three-year period beginning September 1, 2009. A description of the project: The project investigates nonlinear partial differential equations of Monge-Ampere type (i.e., equations involving the Jacobian determinant of a map) arising in the mathematical description of numerous optical, acoustic, and electromagnetic applications, in particular, in lens and reflector antenna design. The questions concern existence, uniqueness and regularity of solutions. The project has connections, interactions, and applications within several areas in mathematics and outside.