Maximum Principles for an Unsaturated Flow Problem
非饱和土壤水流方程的极值原理

Maximum principles are studied for the problem of the fluid movement in unsaturated soils and its numerical scheme, and the maximum principles are theoretically proved to be true for the continuous problem and the corresponding numerical discrete problem. This shows that maxima and minima attain only at boundary points under certain conditions, hence particular physical properties are described. All these are important for the reserach of infiltration and evaporation.