Welcome to our Tree ! (well, not exactly...)
The Graph you see down here is a DAG (directed acyclic graph) that maps together the course bundles or courses of MathNodes (use ctrl + b to switch between the two views, or click on the bottom in the down left button). The nodes represent the courses or bundles, and a descending edge from node A to node B means that you need a certain understanding of node A in order to understand node B. In order to keep our graph intellegible, we chose the prerequisite relation to be transitive: if course C is a prerequisite for course B and B is a prerequisite for course A, we might freely use notions from course C in course A, although it doesn't appear in the graph.
Use the dedicated button to find your learning path, that is what you need to learn in order to understand new notions !
Why do we call it a tree, although it is not the case, neither biologically nor mathematically ? Well, mathematically, it's sort of a tree in a directed way. But the most important thing is that, like a tree, it keeps on growing, and probably will for a while...