You can also watch 1 after learning. The core knowledge of complex variable function and vector analysis, as well as some commonly used functions and transformation methods are condensed. 2. Partial differential equations. 3. Spatial analytic geometry 4. Advanced geometry. Both number theory and group theory do not need the basis of high numbers, although it is difficult and the content is not practical. After reading advanced calculus, you can also watch lectures on topology and functional analysis, and then you can learn more advanced differential geometry. After advanced algebra, there are abstract algebra courses …