2. Chen Jingrun questioned the "tower-in-the-tower problem" in China's "On the Prime Number of Heaps", and put forward specific suggestions for improvement, which promoted the development of mathematics (questioning is the basis of perfection, and questioning is friendly).
3. The German mathematician Schubert questioned a theorem in Euclid's Principles of Geometry: the sum of the internal angles of a triangle is equal to 180. For more than two thousand years, people have always thought that this is a universal theorem, and scientists are more convinced of the truth of this theorem. However, Hubert's question promoted a sudden change in mathematics. German mathematician Riemann was inspired by the thought of external karting, which made the non-Euclidean set break ground. Riemann pointed out that Euclidean geometry does not apply to all spaces. For example, on the earth sphere, the sum of the internal angles of the triangle is greater than 180. Don't be afraid of authority.