# Faculty News Briefs

### May 2007

On April 26, 2007 Professor Tom Braden gave the first of a series of two talks in the seminar *Basic Notions* in the Department of Mathematics at Hebrew University in Jerusalem. The title of the talk was *Counting Faces of Polytopes and Geometry of Toric Varieties.* On March 18 he gave a talk at a one-day mini-conference on *Toric Varieties, Polytope Duality, Mirror Symmetry, and Koszul Duality.* The title of the talk was *Polytope Duality and Koszul Duality.*

On March 28, 2007 Professor Erin Conlon gave an invited seminar talk in the Division of Biostatistics, University of Minnesota, and on April 12 she gave an invited seminar talk in the Department of Biostatistics at Boston University. The titles of both talks were *Statistical Methods for Integrating Multiple Sources of Genomic Data.* Erin was also recently invited to serve on a panel at the National Science Foundation to review proposals.

Professor Richard S. Ellis recently served on a panel at the National Science Foundation that reviewed proposals.

On April 2, 2007 Visiting Assistant Professor Roman Fedorov gave a talk at the seminar *Geometry-Algebra-Singularities-Combinatorics* at Northeastern University. The title of his talk was *Isomonodromic Deformations and Affine Lie Groups.*

Professor Paul Gunnells was a co-organizer of a special session entitled *Arithmetic Geometry and Automorphic Forms,* held during the weekend of April 14-15, 2007 at the meeting of the American Mathematical Society in Hoboken, NJ. On the Friday before the meeting he gave a talk in the Collaborative New York Number Theory Seminar at the CUNY Graduate Center in New York City. The title of the talk was *Automorphic Forms and the Cohomology of Arithmetic Groups.*

On April 26, 2007 Professor Farshid Hajir gave a colloquium entitled *Recent Advances in Galois Theory* at Emory University.

Professor Markos Katsoulakis reports on the following three items.

His article entitled *Intermittency, Metastability and Coarse Graining for Coupled Deterministic Stochastic Lattice Systems* has been included in the list of *High-Profile Articles* of 2006 for Nonlinearity http://herald.iop.org/non/m7/cid/215282/link/682>. This collection consists of the top-downloaded papers published in 2006.

Markos was one of the invited speakers in the 2007 John H. Barrett Memorial Lectures at the University of Tennessee in Knoxville, held during the period April 28Ò30, 2007. The theme of the series this year was *Multi-Scale Modeling and Simulation in Materials Science.* Details on the series including the list of speakers are available at http://www.math.utk.edu/Barrett/.

Markos was invited to participate at the *Applied Mathematics Research-PI (Principal Investigators) Meeting* organized by the Office of Advanced Scientific Computing Research at the Department of Energy. The meeting will take place at the Lawrence Livermore National Laboratory during the period May 22Ò24, 2007.

A paper by Visiting Assistant Professor Yorghos Tripodis and Dr. J. Penzer of the London Schol of Economics was published in the April 2007 issue of Journal of Forecasting. The paper is entitled *Single-Season Heteroscedasticity in Time Series.*

### April 2007

On February 26, 2007 Professor Qian-Yong Chen gave a talk entitled *A New Multipoint Flux Approximation for Reservoir Simulation* at the 2007 Reservoir Simulation Symposium at Houston, TX.

The paper *Symplectic Symmetries of 4-Manifolds* by Professor Weimin Chen and Slawomir Kwasik has been published in Topology 46, no. 2 (2007), 103-128.

On February 23, 2007 Visiting Assistant Professor Roman Fedorov gave a talk entitled *Frobenius Manifold Structures on the Spaces of Abelian Integrals* at the Infinite-Dimensional Algebra Seminar at MIT.

Professor Jenia Tevelev gave a talk entitled *Modular, Tropical, and Log Canonical Compactifications* at the University of Michigan/Ohio State University Weekend Algebraic Geometry Workshop held March 24Ò25, 2007 in Columbus, Ohio. He also gave a talk entitled *Embedding Tropical Stuff in Buildings* at the conference *Buildings and Combinatorial Representation Theory* held March 26Ò30 at AIM in Palo Alto, California.

### March 2007

Professor Weimin Chen gave an invited talk at the workshop *Quantum Cohomology of Stacks and String Theory,* which was held at the Institut Henri Poincare in Paris during the period February 12Ò16, 2007. The title of his talk was *Pseudoholomorphic Curves in the Context of Orbifolds.* The workshop was part of the program *Trimester on Groupoids and Stacks in Physics and Geometry 2007* at the Institut Henri Poincare.

On February 4, 2007 Professor Rob Kusner hosted a conversation with Congressman John Olver on the Sunday-noon WMUA (91.1 FM) public affairs program FOCUS. They discussed transportation issues involving energy, the environment, and foreign policy; Congressman Olver is the new chair of the House Appropriations Subcommittee on Transportation. On March 4 Rob hosted Computer Science colleagues Brian Levine and Mark Corner along with the Town of AmherstÌs IT director Kris Pacunas in a conversation on the Community Wireless Project and its implications for community and economic development in Amherst.

Visiting Assistant Professor Ralf Schiffler attended the *Workshop on Representation Theory and Related Areas,* which took place at the Universidad de la Republica in Montevideo, Uruguay during the period February 26Ò28, 2007. At the workshop he gave a mini-course consisting of three lectures on *Cluster Algebras and Cluster Categories*.

Professor Jenia Tevelev has been named a 2007 recipient of a Sloan Research Fellowship. This year 118 fellowships were awarded, of which 20 were in mathematics. These extremely competitive awards, presented annually by the Alfred P. Sloan Foundation to researchers throughout the sciences, are *intended to enhance the careers of the very best young faculty members in specified fields of science.*

### February 2007

During the week January 29 Ò February 2, 2007 Professor Tom Braden participated in the workshop *Geometric and Topological Combinatorics* at the Mathematisches Forschungsinstitut Oberwolfach in Germany. On January 29 he gave a talk entitled *Combinatorics of Arrangements and Topology of Hypertoric Varieties.*

On January 23, 2007 Professor Farshid Hajir gave a talk in the number theory seminar at the University of Arizona. The title of his talk was *Finitely Ramified Galois Groups via Iteration.*

Professor Panos Kevrekidis was extremely busy during the winter break. On December 6 and 7, 2007 he visited the University of Crete at Heraklion, and during the period December 13Ò16 he participated in the workshop on Coherent Nonlinear Optics of Artificial Media at the University of Lisbon. He then accepted an invitation to participate in the Dynamical Systems Program at the Mathematical Sciences Research Institute in Berkeley during the period January 6Ò27. During that time he also visited San Francisco State University. In each of these venues, Professor Kevrekidis delivered invited lectures about his recent work on solitary waves in spatially and temporally periodic media.

During January 2007 Professor Rob Kusner visited Atlanta, Athens (Georgia), and Salt Lake City for research collaborations. He lectured at both the University of Georgia and Georgia Institute of Technology.

Visiting Assistant Professor Ralf Schiffler spent four weeks at the Universit» Claude Bernard in Lyon, France, where he continued a joint research project with his colleagues. He also gave a talk at the local algebra seminar entitled *Des ModÀles G»om»triques pour les AlgÀbres Amass»es.*

On January 26, 2007 Professor Jenia Tevelev gave a talk at the algebraic geometry seminar at Columbia University. The title of his talk was *Geometry of Chow Quotients of Grassmannians.* During 2006 he published the following papers.

Geometry of Chow Quotients of Grassmannians (with Sean Keel), Duke Math. J. 134, no. 2 (2006), 259-311

HilbertÌs 14-th Problem and Cox Rings (with Ana-Maria Castravet), Compositio Math. 142 (2006), 1479-1498

Compactification of the Moduli Space of Hyperplane Arrangements (with Paul Hacking and Sean Keel), J. Alg. Geom. 15 (2006), 657-680.

### January 2007

A paper by Professor Richard S. Ellis and two former Ph.D. students in our department, Marius Costeniuc and Peter Otto, has been accepted for publication in Journal of Statistical Physics. The 60-page paper is entitled *Multiple Critical Behavior of Probabilistic Limit Theorems in the Neighborhood of a Tricritical Point.* After receiving his Ph.D. in 2005, Marius spent a year as a postdoctoral associate at the Max Planck Institute for Mathematics in the Sciences in Leipzig, Germany. He is currently enrolled in the Master of Advanced Studies Program in Finance in Zurich, Switzerland. Peter received his Ph.D. in 2004. After holding temporary positions at Gettysburg University and Union College, he now has a tenure-track position at Willamette University in Salem, Oregon.

Professor Rob Kusner was recently invited to serve on a National Science Foundation panel reviewing proposals in geometric analysis.

Visiting Assistant Professor Ralf Schiffler attended the winter meeting of the Canadian Mathematical Society in Toronto. He gave a talk at the meeting entitled *m-Cluster Categories and m-Replicated Algebras*.