This lecture covers topics such as weak convergence, more on Poincaré inequality, subsequence convergence, Gagliardo-Nirenberg-Sobolev theorem, scaling arguments, and properties of weak convergence in Banach spaces. The instructor discusses theorems related to Morrey's, Rellich-Kondrachov, and projection, as well as the concept of weak convergence in Banach spaces. The lecture also explores the definition and properties of weak convergence in Banach spaces, including the notion of dual spaces and reflexive spaces.