One of the most important topics in all of discrete mathematics is relations. It's the bedrock, in turn, of one of the most important software technologies — relational database management systems.
In this mini course, my sole aim is to get you comfortable with some of the most important ideas in relations. This course isn't meant to be a proof dump, proving theorem after theorem with respect to relations; instead, it's meant to intuitively introduce the core concepts of the subject.