Wei Dongyi, an associate professor at Peking University's School of Mathematical Sciences, listed two sets of primary and secondary school math workbooks he edited on his Bilibili account. On the evening of August 22, links to the two workbooks were removed. Before that, cumulative sales of these teaching aids had exceeded 26,000 copies, with estimated sales revenue over 1 million yuan.
On the evening of August 18, Wei Dongyi updated his Bilibili account with a video titled "An Interesting Math Problem," demonstrating a solution to a fourth-grade primary school math problem and labeling it "Wei Dongyi Chief Editor: Mathematical Ability." Early after the workbooks went on sale, some netizens doubted the authenticity of the account and products. Longmen Bookstore Press confirmed the series officially launched this week, sold both on official accounts and Wei's personal account, oriented toward advanced training, and personally chief-edited by Wei Dongyi himself.
On major e-commerce platforms, some merchants are also selling the workbooks. For example, Douyin's "Banxuejiang Official Flagship Store" has sold over 10,000 orders. At around 1 a.m. on August 23, more than 150 people were still watching the store's livestream.
News that Wei Dongyi's teaching aids sparked controversy and were pulled under pressure spread rapidly across self-media. The small-store customer service said the two math workbooks were not delisted network-wide, but only had their sales channels adjusted after "selling out." Bilibili's official customer service responded that consumers who successfully purchased the workbooks in the Bilibili store can still contact the merchant for after-sales matters.
Born in 1991 in Jinan, Shandong, Wei Dongyi is an assistant professor at Peking University, with research interests including partial differential equations and geometric analysis. He has achieved a series of important advances on the regularity of the three-dimensional Navier-Stokes equations and the linear damping of two-dimensional incompressible Euler equations. He also collaborated on major results in random matrix theory research. In 2020, Wei Dongyi and Yang Shiwu, assistant professor at the Beijing International Center for Mathematical Research, improved research on the long-time decay behavior of solutions to the defocusing semilinear wave equation, resolving the conjecture on pointwise decay of one-dimensional solutions proposed by Terence Tao and others. From February 2026, Wei Dongyi was formally appointed as a tenure-track associate professor at Peking University.
