In which branches of the topology are generated. Look at the latest basic geometric topology, and you will gain a lot. If you read books on algebra and topology, it will be difficult and a waste of time. If you just want to know, it is enough to read popular science books that introduce one-dimensional, two-dimensional, three-dimensional, four-dimensional and high-dimensional spaces, and you can get it quickly. Sometimes the theory introduced by suitable popular science books is easy to understand and profound, while some professional books are not difficult enough.
Four-dimensional space and above belong to high-dimensional model.
High-dimensional model is divided into two concepts: mathematics and physics.
Mathematically, there are many models in multidimensional. Theoretically, the dimension can be very high. There are many models. However, few people satisfy the property of exchange invariance, so some people think that four-dimensional space is the physical upper limit. But some people think that there will be higher-dimensional physics. Thinking is beneficial to intelligence, because it is only limited by mathematical conditions.
Physically, there are many models in many dimensions. Theoretically, the dimension can't be very high. In order to explain the infinity of the universe as a whole, it is necessary to introduce multi-dimensions, generally four-dimensional space-time (a pair of relative composition properties), and some other finite countable dimensions, so there are not many models that may be established in physics. Thinking is very difficult because it is bound by physical phenomena.
Huanggeshi