先给出这些问题的提法，然后使用列紧性原理和极值原理证明了上述二阶椭圆型方程边值解的存在性和唯一性。

Fristly the boundary value problems for the equations is formulated, and then by using the compactness principle, the existence of solutions for the above problems is proved.

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讨论了二阶非线性椭圆型方程在多连通区域上的间断边值问题。

The article deals with the discontinuous boundary value problem for nonlinear elliptic complex equations of second order.

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本文对一般的二阶线性椭圆型方程，在满足内部锥条件时，证明了其强极值原理。

In this paper, the strong extremal principles have been proved for second or der linear elliptic equations on the domain which satisfies an interior cone condition.

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