This article uses idea of partial boundary condition theory for second order linear degeneracy differential equations with nonnegative characteristic form, to carry out studying initial-boundary value problem formulation, uniqueness and existence of some nonlinear degeneracy parabolic equation.This article is divided into six parts.Chapter1briefly introduces physical background of non-Newtonian multilateral percolation equation, as well as the research situation in the world;chapter2introduces initial-boundary value problem formulation for second order (non)linear degeneracy differential equations with nonnegative characteristic form;chapter3studies double degenerate polypropic filtration equation: and gets week solution with initial value u0∈Lm+1(Ω),ρα/2▽u0m∈L∞(0, T; L2(Ω));chapter4gets the existence of W21,1week solution for some parabolic partial differential equation: Lu=aij(x,t)uxixi+bi(x,t)uxi+c(x,t)u-φt(u)=f(x,t), in(x,t)∈QT, chapter5studies and gets unique week solution for some convection diffusion equation: with initial-boundary condition under p>2,p-2/2>α>0, α≤1; chapter6studies some singular diffusion equation: and gets:(1)0<α<p-1, for any u0∈L∞(Ω) and pa|▽u0|p∈L1(Ω), there exists unique week solution of initial-boundary condition,(2) α≥p-1, dispense with boundary value, the equation admits at most one week solution with initial value. |