Authors’ Note

The separation of computer science from mathematics greatly impoverishes both. The lectures that this book is based on were my attempt to show how these two activities—an ancient one going back to the very beginnings of our civilization and the most modern one—can be brought together.

I was very fortunate that my friend Dan Rose, under whose management our team was applying principles of generic programming to search engine design, agreed to convert my rather meandering lectures into a coherent book. Both of us hope that our readers will enjoy the result of our collaboration.

—A.A.S.

The book you are about to read is based on notes from an “Algorithmic Journeys” course taught by Alex Stepanov at A9.com during 2012. But as Alex and I worked together to transform the material into book form, we realized that there was a stronger story we could tell, one that centered on generic programming and its mathematical foundations. This led to a major reorganization of the topics, and removal of the entire section on set theory and logic, which did not seem to be part of the same story. At the same time, we added and removed details to create a more coherent reading experience and to make the material more accessible to less mathematically advanced readers.

While Alex comes from a mathematical background, I do not. I’ve tried to learn from my own struggles to understand some of the material and to use this experience to identify ideas that require additional explanation. If in some cases we describe something in a slightly different way than a mathematician would, or using slightly different terminology, or using more simple steps, the fault is mine.

—D.E.R.