本文讨论了一类四阶微分算子的左定边界条件,利用自共轭扩张的正定性来研究左定问题.通过自共轭微分算子的系数、区间端点以及边界条件给出了问题左定性的充要条件,并相应地得到了所有四阶自共轭微分算子的左定边值矩阵的情形.
In this paper,we discuss the left-definite boundary conditions of a class of fourth-order differential operators,and we study the left-definite problems by the positive definiteness of the self-adjoint extension.Besides,we give the necessary and sufficient conditions of left-defined problem by means of the cofficient of self-adjoint differential operators, the endpoints of interval and boundary conditions.Moreover,we correspondingly obtain all of the left-defined boundary matrix of fourth-order self-adjoint differential operators.