给出了无穷区间上一类抽象连续可微函数族相对紧性判定的一个充要条件,并应用它获得了二阶微分方程终值问题解的存在性.
A sufficient and necessary condition is given for relative compactness of a class of abstract continuous function groups. By applying it, the existence of solutions of terminal value problems for second order differential equation is proved.