## About Stephen Siegel

I am an Associate Professor in the Department of Computer & Information Sciences, with joint appointment in the Department of Mathematical Sciences, at the University of Delaware. We are located in the city of Newark, state of Delaware, in the United States. I work in formal methods, which involves applications of logic to problems in computer science. I am particularly interested in verification of concurrent and distributed programs, using model checking, deductive reasoning, symbolic execution, and other methods. I teach classes in Parallel Computing, Logic, Model Checking, and Software Engineering.

## About the header image

The image seen at the top of each page was generated by Jaap Scherphuis’s Tiling Viewer, convex pentagonal tiling N5-15. It is the 15th convex pentagonal tiling to be discovered, found by Casey Mann, Jennifer McLoud-Mann and David Von Derau in 2015. A theorem states these 15 are all the convex pentagonal tilings of the plane. A computer-assisted proof of this theorem was produced by Michaël Rao in 2017. It has been reported that Thomas Hales has independently confirmed the result.