I took Prof. Gallier (the author of this document)'s class when I was a graduate student at Penn.
http://www.cis.upenn.edu/~jean/home.html
It is one of the class I enjoyed the most when I was there. Some of his other books are quite enjoyable as well.
Dr. Gallier's PhD work was focused on logic, but his current research has a lot to do with computer graphics and computational geometry. He spent a long time study graduate-level algebraic geometry and algebraic topology while having the duty to be a professor at computer science department. His stories is always an inspiration for me to learn more.