题目：The a priori estimates for degenerate Hessian equations
报告摘要：In this talk, I will report some methods of the a priori estimates for the Dirichlet problem for degenerate Hessian equations which is developed by Krylov in 1980s and 1990s when studying Bellman equations. Krylov's proof was further simplified by Ivochkina, Trudinger and Wang in 2004 in the case of Hessian equations. The main constent of this report is based on the paper of Ivochkina, Trudinger and Wang. I will also introduce an open problem in this topic and some developments for it.