Regularity of Solutions to Second Order Elliptic Equations with Discontinuous Coefficients
间断系数的二阶椭圆型方程解的正则性

The mathematical problem discussed in the paper is derived from the electric field with discontinuous dielectric constants arising in biology and physics. The author will study the existence and regularity of solutions to semi-linear second order elliptic equations with discontinuous coefficients. The pseudo differential operator is a basic tool in the present paper.