Topology is the study of some properties that geometric figures or spaces can remain unchanged after continuous shape changes. It only considers the positional relationship between objects, without considering their shapes and sizes. In topology, important topological properties include connectivity and compactness.

Discrete mathematics is the general name of related branches of mathematics that study the mathematical structure and properties of discrete objects. Compared with real number theory, mathematical analysis and differential equations, discrete mathematics is characterized by dealing with discrete objects, and its research contents usually include (but are not limited to) graph theory, set theory, combinatorial mathematics, mathematical logic, various algebraic structures and other mathematical objects that can be discretized or enumerated.