# Faculty News Briefs

### 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*.

### December 2006

Visiting Assistant Professor Ana-Maria Castravet gave a talk on November 7, 2006 in the Harvard-MIT Algebraic Geometry Seminar. The title of her talk was *HilbertÌs 14th problem and Cox Rings,* based on joint work with Jenia Tevelev.

Professor Paul Gunnells gave a talk on November 15, 2006 at the Algebra and Number Theory Seminar at the University of Maryland. The title of his talk was *Quadratic Weyl Multiple Dirichlet Series.*

Professor Farshid Hajir gave a colloquium on November 3, 2006 at McMaster University in Hamilton, Ontario, Canada. The title of his talk was *Galois Groups and Dynamics on the Projective Line.*

Professor Panos Kevrekidis was informed on November 2, 2006 that his paper *Deciding the Nature of the Coarse Equation through Microscopic Simulations: The Baby-Bathwater Scheme* was chosen as the next SIGEST selection from Multiscale Modeling and Simulation, a journal published by the Society for Industrial and Applied Mathematics (SIAM). Cowritten with Ju Li, C.W. Gear, and I. G. Kevrekidis, the paper will appear in issue 49-2 of SIAM Review in June 2007. The purpose of the SIGEST propgram is to make the more than 10,000 readers of SIAM Review aware of exceptional papers published in SIAMÌs specialized journals. The paper by Panos and his collaborators was chosen by the editors of SIAM Review *for the importance of its contributions and topic, its clear writing style, and its broad interest for the SIAM community.*

Professor Jenia Tevelev gave a talk on October 31, 2006 at the Commutative Algebra and Algebraic Geometry Seminar at the University of California at Berkeley. The title of his talk was *Modular, Log Canonical, And Tropical Compactifications.* He gave another talk on November 3 at the Algebraic Geometry Seminar at Stanford University. The title of his second talk was *Geometry of Chow Quotients of Grassmannians*.