# Research: Applied Math

## Faculty

#### Maya Chhetri

My research interest is in studying the solutions of nonlinear elliptic PDEs and ODEs. In particular, I study the questions of existence, uniqueness and multiplicity of solutions of nonlinear boundary value problems in ODEs and elliptic PDEs, and stability of solutions of corresponding evolution equations.

#### Yu-Min Chung

Yu-Min Chung received his Ph.D. in Mathematics from Indiana University Bloomington in 2013 specializing in computational mathematics. His main research focuses are computational topology and applications to data analysis, called Topological Data Analysis. He has been collaborating with researchers from different scientific disciplines, including those from Dartmouth College to investigate ice at the Arctic, and those from Harvard Medical School to study human red blood cells. Chung’s other research interest is computational dynamical systems. He and his group developed one of the first algorithms to compute inertial manifolds, an object from dynamical systems. Prior to UNCG, Chung taught previously at the College of William & Mary, University of Kansas, and Indiana University. Chung has also advised undergraduate honor research students, and REU students, and his students have presented their research work in local and national conferences.

#### Igor Erovenko

I have been working on projects in different areas of mathematical biology including the evolution of cooperation, game-theoretic models of infectious diseases, and theoretical ecology. The mathematics I use in these projects includes game theory, optimization, ordinary differential equations, and stochastic processes.

#### Richard Fabiano

I am interested in questions related to modeling, control, and approximation of infinite dimensional linear systems. In particular I study systems governed by either delay-differential equations or partial differential equations which arise in modeling flexible structures. The mathematics we use includes functional analysis, differential equations, and control theory.

#### Thomas Lewis

I am interested in the development, implementation, and analysis of numerical methods for approximating nonlinear partial differential equations. Nonlinear PDEs arise in stochastic optimal control, optimal mass transport, and materials science. My research has focussed on the Hamilton-Jacobi-Bellman equation, the Monge-Ampere equation, and the Cahn-Hilliard equation.

#### Jonathan Rowell

My research has been motivated primarily by problems in ecology, evolution, and other areas of biology, but I am broadly interested in dynamical systems and general transport and/or diffusion models. The mathematics of my work includes functional analysis, ordinary and differential equations, difference equations, linear algebra, and game theory.

#### Jan Rychtář

I am interested in applications of mathematics in a wide range of fields. I have collaborated with researchers from biology, sociology and computer science. My work consists in building and analyzing a mathematical model of a phenomena of particular interest of the researcher. The mathematics involved ranges from game theory, ODEs, probability and stochastic processes and graph theory.

#### Ratnasingham Shivaji

Study of nonnegative solutions to partial differential equations, arising in the modeling of natural phenomena that is dominated by reaction and diffusion. Recent results focus on singular problems, problems with nonlinear diffusion and effects of nonlinear boundary conditions. His research has been funded by the National Science Foundation (NSF) and by the Simon’s Foundation. Currently, he serves as the PI on an NSF Math Ecology Grant. He has authored over one hundred and thirty research papers. He is a member of the Editorial Board of several mathematics journals. To date, he has directed one postdoctoral student, fifteen Ph.D. students (11 graduates, 4 current), fourteen M.S. graduates and nineteen undergraduate research students (18 graduates, 1 current).

#### Yi Zhang

Yi Zhang received his Ph.D. in Mathematics at the Louisiana State University, his M.S. in Applied Mathematics as well as his B.S. in Mathematics from Wuhan University, China. Prior to joining the faculty at UNCG, he was a postdoctoral research associate at the University of Tennessee, Knoxville and the University of Notre Dame. He has taught a variety of mathematics courses, including several advanced computational/numerical mathematics courses. His research interests include numerical solutions of deterministic and stochastic partial differential equations, finite element methods, variational inequalities, PDE-constrained optimization and numerical optimization.