# Department of Mathematics

# News

- Meet Minwoo Bae! (06/21/2017)
Meet one of our graduate students and summer research interns, Minwoo Bae!

This Summer I am going to continue the work on developing algorithms to solve computational problems in the field of Mathematical Neuroscience under the supervision of Professor Amarasingham. His laboratory is currently engaged in the development and application of tools for inferring neuronal connectivity maps from extracellular spike data obtained from electrophysiological brain recordings in in vivo conditions. This is in collaboration with G. Buzsaki’s experimental lab at NYU. There are many mathematical challenges, ranging from the development of biophysical models to the development of nonparametric spike train analysis tools. Regarding the latter, some of the major obstacles are computational. A theory is in place for performing connectivity inference, drawing from previous tools developed in the laboratory, but at current data scales the computational costs are prohibitive. My summer research aims for developing algorithms to accelerate these computations. There are two principal approaches I will pursue. The first will involve accelerating the computation of distributions of sums of random variables, in the style of the fast Fourier transform (FFT), and related tools. The challenge is accommodating nontrivial dependency structures (expressed as graphs; so-called “graphical models”) among these random variables. I will research approaches to handling these elaborations. A second approach is to use asymptotic approximations. I will research the literature to see what bounds are available, adapting them as necessary, to justify and combine asymptotic approximations. I will apply the ideas developed in these investigations to in vivo neurophysiology data, in the context of the laboratory’s other work.

Since 2011, I had been working as a software developer in Manhattan. Since I designed and developed several web applications for a HIV research team, I naturally gained interest in how a disease is transmitted though a network. In 2014, I had the honor of being selected as Young Talent in the Field of Software by the South Korean government, which provided me with a fund for advanced study of mathematics and computer science. I used the fund for some graduate-level coursework in computer science to study random processes on a network. During this part-time student experience, I realized that without the advanced mathematical foundation, it would be very difficult to proceed much further in this kind of studies. This led to my decision to fully return to school to pursue studying Mathematics since 2015. Now in 2017, I am very excited by the fact that it is possible to tackle many technical challenges ranging from biology to artificial intelligence by using Mathematical concepts and techniques. This why I am passionate about Mathematics.- Haris Nadeem placed 8th in CUNY Math Challenge! (06/16/2017)
Haris Nadeem placed 8th in this year's CUNY Math Challenge. He will be receiving an award from CUNY central for placing in the top ten. He is a dual pure math and computer science major.

- Meet Pavel Javornik! (06/14/2017)
Meet one of our undergraduates and summer research interns, Pavel Javornik!

This summer I will be continuing my work under the mentorship of Dr. Patrick Hooper. Our current project is to describe the dynamical properties of geodesic flows on non-compact surfaces composed entirely of boundary unions of various polyhedrons. Certain characteristics of these infinite surfaces, such as the symmetries of the canonical forms of their quotient spaces, determine the behavior of geodesic flows given properties of said flow (such as their initial trajectories). The goal this summer is to adapt various methods used in studying infinite surfaces constructed from compact translation surfaces to better understand surfaces that might admit transformations of geodesic flows in the form of rotations. Much of the study of Veech surfaces is applicable to certain rational billiards problems on infinite surfaces like the Ehrenfest-Wind Tree Model, but these transformations often admit reflections off of boundaries in the form of perfectly elastic collisions. The translation surfaces and (consequently) Veech groups of these infinite surfaces have symmetrical properties unlike those of surfaces constructed of polyhedrons. Understanding how these boundaries might affect geodesic flow on flattened structures is key to understanding their dynamical properties.

What drives my work is my love for mathematics. Studying the underlying structures of objects such as manifolds fascinates me. With low-dimensional topology there is a geometric intuition when trying to characterize these kinds of surfaces. Describing the homology classes of non-compact, infinite (possibly infinite genus) surfaces in the form of their compact covering/translation spaces is a somewhat novel undertaking. There's an extraordinary number of possibilities in this realm of mathematics and they all begin with asking simple questions that begin to unravel the mysteries of the objects we study.- Two undergraduate students excel on the Putnam exam (05/15/2017)
The Putnam examination is a nationwide mathematics examination requiring exceptional ability and creativity to achieve a non-zero score. Two CCNY seniors, Allen Kim and Gautam Ramasubramanian, did exceptionally well, placing 408th and 813th nationwide. Congratulations to both, who will graduate in Spring 2017!

- 11 CCNY Mathematics students to begin doctoral programs with support (05/15/2017)
Eleven students finishing their MS degrees in Spring 2017 will begin doctoral programs in Fall 2017 with institutional financial support at a number of excellent institutions, including the University of Minnesota, the University of Waterloo, the University of Illinois, Arizona State University, Syracuse University, the CUNY Graduate Center, the University of Pennsylvania, and Stevens Institute of Technology.

The mathematics department congratulates all graduates!

- Professor Brooke Feigon receives the President's Outstanding Service Award! (05/09/2017)
Prof. Brooke Feigon is the recipient of the President's Outstanding Service Award. This award recognizes both the creativity and commitment of a full-time faculty member and the impact that s/he has had on student learning through a combination of innovative approaches in mentoring, research, teaching and/or scholarship. Awards will be made annually to up to three faculty members who have demonstrated extraordinary service to students, to scholarship and to the College. This award recognizes the importance of faculty participation in the governance of the institution and its significant impact on the College and the greater College community.

- Kenneth Arrow, CCNY Graduate & Nobel Laureate, has died (02/23/2017)
Kenneth Joseph "Ken" Arrow (August 23, 1921 – February 21, 2017) was an American economist, writer, and political theorist. He was the joint winner of the Nobel Memorial Prize in Economics with John Hicks in 1972. To date, he is the youngest person to have received this award, at 51.

In economics, he was a figure in post-World War II neo-classical economic theory. Many of his former graduate students have gone on to win the Nobel Memorial Prize themselves. His most significant works are his contributions to social choice theory, notably "Arrow's impossibility theorem", and his work on general equilibrium analysis. He has also provided foundational work in many other areas of economics, including endogenous growth theory and the economics of information.

Arrow remained active on the international scene through a variety of initiatives including trustee of Economists for Peace and Security and a member of the Advisory Board of Incentives for Global Health, the not-for-profit behind the Health Impact Fund until his death.