一类具正系数的四阶对称微分算子的极限点型  

On the Limit-point Case of a Class of Fourth-order Ordinary Differential Operators with Positive Coefficients

作　　者：郭占宽[1] 孙爱文 

机构地区：[1]内蒙古大学数学系 [2]伊克昭盟水文勘测局,内蒙古东胜017000

出　　处：《内蒙古大学学报（自然科学版）》2001年第4期367-372,共6页Journal of Inner Mongolia University：Natural Science Edition

基　　金：国家自然科学基金资助项目 (1 9871 0 3 7)

摘　　要：将形如 L =(py″)″-(qy′)′的微分算式分解为两个二阶微分算式的乘积 ,在 L有正的下界的条件下 ,L的亏指数即是上述两个微分算式的亏指数之和 .从而为这种四阶微分算式的极限点的判别提供了新的简捷的方法 。Some fourth order ordinary differential expressions are decomposed into the products of two second order ordinary differential expressions,when L has a positive belower bound,the deficiency index of L is the sum of the deficiency indices of the two second order differential expressions.Thus,we proposed a new and concise method for judging the fourth order differential expressions to be limit point case,and gave a new sufficient condition of limit point case.

关 键 词：微分算子 亏指数 极限点 黎卡提方程 四阶对称 正系数 

分 类 号：O175.3[理学—数学]