I immediately apologize for my English, Google translator is my assistant. I couldn't find the information in my own language. My question is addressed to people who understand mathematics. I hope for your help.
As you know, any branch of mathematics cannot exist by itself. Accordingly, as a student, having knowledge at the level of limits/integrals, having opened a textbook on category theory, homological algebra or topological groups (all these as examples), I will not be able to understand anything there. At the same time, there is no explanation anywhere regarding which specific sections of mathematics and at what level should be mastered before starting to study, again, for example, manifolds and cell complexes. I also understand that people who study mathematics as a specialty somehow come to understand what and in what order they should study. But I am not a student of mathematical directions, and I plan to study mathematics for myself. Not as an applied discipline, but specifically mathematics for mathematics. Which particular branch of mathematics would I like to study? I don't know. I would like to take a look at the cutting edge of this science, and what questions are being raised there. It is obvious that this region is very wide, and the issues there are sometimes diametrically opposed. I just don't want to spend time studying everything, because mathematics is not easy. To study random processes when I actually find topology interesting? What for?
In general, my question. What is the relationship between the beginning and the edge of mathematics? Or that there is a root and branches (if mathematics is a tree)? Is there some kind of math roadmap? Or a web? I would like to see its most complex, advanced areas, and what you should know to start diving into one of them. I've come across similar things before, but they don't cover everything. Once again, please note that I am not interested in applied mathematics. No physics or finance, just pure math, only hard.
I really hope for your help!