Intersection cohomology is introduced by Goresky and MacPherson as a cohomogy theory on singular spaces which admit the Poincare duality. Decades of works show that this cohomology theory share a bunch of good properties such as Lefschetz package, Hodge-Riemann bilinear relation and Hodge theoretic purity. Although the theory is well established in the context of topology and algebra, the de Rham theorem remains open. In this talk I will introduce the basic knowledge of intersection cohomology and present a solution of the de Rham theorem for intersection cohomology when the space is algebraic and admits only equisingularities. This is the joint work with Chen Zhao.

Associated with a Coxeter group W, we may define a Hecke algebra H(W) and an endomorphism algebra E(W), called the Hecke endomorphism algebra. We use the defining relations for Hecke algebras to give a presentation for E(W) over a certain ring and speculate an extension to the integral case which is the key ingredients to categorify E(W) via singular Soergel bimodules.

We are going to recall the definition of partial entropy along expanding foliation, and its regularity with respect to maps.

Consider the approximation of Navier-Stokes equations for a Newtonian fluid by Euler type systems with relaxation. This requires to decompose the second-order derivative terms of the velocity into first-order terms. We use Hurwitz-Radon matrices for this decomposition. We prove the convergence of the approximate systems to the Navier-Stokes equations locally in time for smooth initial data and globally in time for initial data near constant equilibrium states.

Online optimization where the cost function is gradually revealed has a lot of applications in machine learning. Recently, there has been interest in distributed online optimization due to the widespread wireless connection and the emergence of internet of things.

We will discuss recent developments in the representation theory of Lie algebras of polynomial vector fields on algebraic varieties (based on joint results with Y.Billih, J.Nilssen and A.Zaidan).

We present some work on analysis of elliptic PDEs of non-local types. And we give a brief introduction on: some basic maximum principles, existence and uniqueness, classi_cations and Liouville type theorems, Bocher type theorems and the related maximum principles for singular solutions. The focus is on the ideas and related basic estimates behind these research work. We will also discuss some basic estimates for linear equations.

I will survey some recent progress on differential calculus of quivers with potentials and give some applications of it to algebraic geometry and representation theory.