Abstract:

in this paper a class of singular perturbation of nonlocal boundary value problems for elliptic partial differentail equations of hingher order is considered by using teh differential inequalities,the uniformly valid asymptotic expansion of solution is obtained .

Key words: 　Ｄｉｆｆｅｒｅｎｔｉａｌｉｎｅｑｕａｌｉｔｙ, Ｓｉｎｇｕｌａｒｐｅｒｔｕｒｂａｔｉｏｎ, Ａｓｙｍｐｔｏｔｉｃｅｘｐａｎｓｉｏｎ, Ｅｌｌｉｐｔｉｃｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎ, Ｎｏｎｌｏｃａｌｂｏｕｎｄａｒｙｖａｌｕｅｐｒｏｂｌｅｍ．