A graph is technically a set of vertices that are connected to each other by edges. In the real world we can actually use this concept of just having vertices and edges to represent a huge number of different problems. And what we teach in the chapter is a bunch of different techniques for solving common problems you'd fall into when you want to use these gra such as, how do i find the shortest path from one vertice to another? The problem that originally inspired some of these algorithms was trying to electrify large parts of check republic. That's a pretty col vesty.