Graph theory is widely used in many fields, including computer science, physics, chemistry, biology, engineering, economics and sociology. For example, in computer science, graph theory is used to study data structure, algorithm design, network analysis and other issues; In physics, graph theory is used to study molecular structure, crystal structure and other issues; In chemistry, graph theory is used to study chemical reaction mechanism and other issues; In biology, graph theory is used to study protein structure and gene regulation. In engineering, graph theory is used to study circuit design, communication network and other issues; In economics and sociology, graph theory is used to study market structure, social network and other issues.
In a word, graph theory plays an important role in mathematical research. It provides a powerful tool for us to describe and solve various practical problems. With the development of science and technology, graph theory will play a more important role in the future.