Arjun Guha is an Assistant Professor of Computer Science at UMass Amherst. He enjoys tackling practical problems, while adhering to the mathematical foundations of programming languages. For example, his dissertation on JavaScript semantics and type-checking, from Brown University, is used by several other researchers as a foundation for their own work. As a postdoc at Cornell University, he developed a model of software-defined networking (SDN) in the Coq Proof Assistant, which is the foundation for a verified runtime and other SDN tools. For his research, he has developed and contributed to several software systems, such as LambdaJS, Frenetic, and Flapjax.