On April 11, Xiangyu Zhou, member of the Chinese Academy of Sciences and professor at the Academy of Mathematics and Systems Science of Chinese Academy of Sciences, was invited to deliver a Chern Lecture at the "Nankai University's Mathematics Centennial Grand Forum". This year marks the 110th anniversary of the birth of Shiing-Shen Chern, and the lecture is one of the commemorative activities planned for the anniversary. The Executive Vice President of Nankai University Jingjun Xu attended the lecture and presented Prof. Xiangyu Zhou with a forum speaker commemorative certificate.

At the beginning of the lecture titled "Start with the Introduction of Complex Number", in remembrance of Shiing-Shen Chern, Prof. Xiangyu Zhou reminisced about the stories of meeting Shiing-Shen Chern for the first time at one academic event in 1986, and the encouragement, support and help that he had received from Prof. Chern in later years. Then, starting with the Tartaglia-Cardano formula, Prof. Xiangyu Zhou explained the history and the significance of the introduction of complex number and its algebraic form, the historical stages of complex number and the theory of complex variable functions, and specially mentioned the role complex number has played as an important foundation in Chern's remarkable work achievements such as the Chern class.

Prof. Xiangyu Zhou also elaborated systematacially the close connection between the theory of complex variable functions and many important branches of modern mathematics, which, as Prof. Zhou said, reflects the uniformity in mathematics. He took Riemann's conjecture and several important mathematical problems as examples, explained the wonders of theory of complex variable functions, as well as the significant applications of complex variable functions in engineering science and physics.

In the second half of the lecture, starting with the development of numerical solution of equations of higher degree, Prof. Zhou gave a in-depth analysis on the important contribution that ancient Chinese mathematics has made to the development of mathematics in the world, and shared the results of his research related to this field.

After the lecture, Prof. Zhou had discussions with the teachers and students present and answered their questions.