It is a great pleasure for me to recommend Yu Weijian to your graduate school.I taught Yu Weijian Operations Research from March to June 2020. In class, Yu Weijian was active in answering and discussing questions. He often gave original opinions on problems raised on class. For example, when I gave a lecture about the application of the feasible direction method to nonlinear programming problems, he could use analogy to suggest whether this method could be applied to linear programming problems. His excellent logical thinking really impressed me.