**Congratulation to: Danielle Jones, Megan Tracy, Anna Yanchenko, Ziyuan Jin and Siyao Chang**

As the oldest and most distinguished honor society in the country, Phi Beta Kappa offers membership to less than one percent of all undergraduates. Many of the leading figures in American history and culture have begun their careers with election to the society, including seventeen presidents of the United States. As a result, membership is a remarkable accomplishment, both for the student who achieves it and the faculty and staff whose support and guidance has led to this milestone.

The Frank Finger Graduate Fellowship Award for Teaching was awarded to Katelynn Kochalski. This award honors teaching assistant in the College of Arts & Sciences for their recognition of stimulating and organized classroom teaching.

http://trc.virginia.edu/awards/the-dr-frank-finger-graduate-fellowship-for-teaching/

Professor Andrew Obus will receive the University of Virginia All-University Teaching Award for 2014-2015. He was chosen to receive this award along with nine (9) other recipients for their excellence in teaching, research and service accomplishments.

http://trc.virginia.edu/awards/all-university-teaching-award/

In his entertaining and fast-paced performance, Dr. Benjamin shows how to mentally add and multiply faster than a calculator, improve your memory for numbers and figure that days of the week for any day in history... and more!

**Alex Lubotzky (Hebrew University of Jerusalem)**

*Expanders: From One-Dimensional to Multi-Dimensional*

**Lecture 1:*** Expander Graphs and Geometric/Topological Expanders*

Date: Tuesday, November 18, 2014

Time: 5:15-6:15 pm

Location: Physics 204

Abstract. Expander graphs have played an important role, in the last four decades, in many areas of computer science. Recently they have already found applications in pure mathematics. We describe some of this history and present in these three talks some recent efforts to build a high-dimensional theory of expanders. We will start with Gromov's geometric and topological expanders.

**Lecture 2:** *From Ramanujan Graphs to Ramanujan Complexes*

Date: Wednesday, November 19, 2014

Time: 4:00-5:00 pm

Location: Monroe 116

Abstract. Ramanujan graphs are optimal expanders. Their explicit construction is based on deep results of Deligne and Drinfeld in the theory of automorphic forms of GL(2). The work of Lafforgue for GL(d) enables the developments of high-dimensional objects: the Ramanujan complexes. These simplical complexes/hyper graphs enjoy some remarkable properties, being random-like but at the same time very symmetric. We will show how this helps to solve some problems in computer science (e.g., error-correcting codes) and in geometry.

**Lecture 3:** *Coboundry Expanders and Property Testing*

Date: Thursday, November 20, 2014

Time: 4:00-5:00 pm

Location: Monroe 116

Abstract. Another direction of generalizing expanders from graphs to simplical complexes was proposed independently by Linial-Meshulam (in the context of developing Erodos-type theory of random simplical complexes) and by Gromov (when studying overlapping properties). We explain this notion and show a surprising connection with "property testing" which is a subject of fundamental importance, in theory and practice, in computer science.

Alex Lubotzky (Hebrew University of Jerusalem) will give three lectures in November on "Expanders: From One-Dimensional to Multi-Dimensional." These lectures open a new distinguished lecture series, *Virginia Mathematics Lectures*, sponsored by the UVa Department of Mathematics and the Institute for Mathematical Sciences. See details: https://math.virginia.edu/lectures

Professor Andrei Rapinchuk has been appointed the new McConnell-Bernard Professor of Mathematics. This is a chaired professorship previously held by Leonard Scott.

Professor Slava Krushkal received a Simons Fellowship in Mathematics for 2014. To honor the 2014 recipients, the Simons Foundation has placed an ad in the "Science Times" section of the *New York Times (*July 1 edition).

The Simons Foundation: *Advancing Research in Basic Science and Mathematics *