In this paper,we will discuss smoothness of weak solutions for the system of second order differential cquations eith non-negative characteristics.First of all,
In this paper we discuss the quasilinear parabolic equation Ut=△↓(u^α(1-u)^β.△↓u)+B(x,t,u)△↓u+C(x,t,u)which is degenerate at u=0 and u=1.Let u(x,t)be a
In this paper,the concept of the centered sublattice is introduceed for lattice theory and the dis-composition theorem of a lattice is given.Based on the center