# Paul Horn

## Professor; Associate Chair of Graduate St

303-871-2911 (Office)

http://www.cs.du.edu/~paulhorn/

Clarence M. Knudson Hall, 2390 S. York St. Denver, CO 80210

### What I do

I am an Associate Professor of Mathematics at the University of Denver; my role here involves research, teaching classes and advising graduate and undergraduate students. I am also currently the graduate coordinator in the mathematics department.### Specialization(s)

combinatorics, graph theory, probability

### Professional Biography

I received my PhD in 2009 from the University of California at San Diego, advised by Fan Chung, and joined the faculty of DU in the fall of 2013 after postdoctoral positions at Emory University and Harvard University.

I am also closely involved with several research workshops. In particular I co-organize the Rocky Mountains-Great Plains Graduate Research Workshop in Combinatorics (GRWC), which is an annual research workshop for graduate students in combinatorics. I also help organize the graph theory section Masamu Advanced Studies Institute, an annual research workshop in southern Africa.

### Degree(s)

- Ph.D., Mathematics, University of California, San Diego, 2009

### Professional Affiliations

- American Mathematical Society
- Society for Industrial and Applied Mathematics

### Research

One recent project I've been involved in is the development of notions of 'curvature' for graphs. Curvature, in the study of manifolds (which are objects that 'locally' look like Euclidean space, in the way the surface of the earth 'locally looks like a plane), is a measure of how a space expands 'locally.' The notion of curvature we introduced has allowed me and my collaborators to prove graph theoretical analogues of a number of results from Riemannian geometry; specifically a graph theoretical version of the 'Li-Yau inequality' along with many consequences.

#### Areas of Research

#### Key Projects

- Collaboration on problems in graph theory, and geometric analysis on graphs
- Collaborative Research: Rocky Mountains-Great Plains Graduate Research Workshops in Combinatorics
- Curvature and Geometric Analysis of graphs