nonempty close subset中文什么意思

例句与用法

1. A time scale t is an arbitrary nonempty closed subset of the real numbers . in the paper , we study quasilinearization and the monotone iteration methods for second - order nonlinear boundary value problems on time scales
   时间模t _ 1是实数集上的一个非空闭子集，本文讨论了时间模上二阶非线性边值问题的拟线性方法和单调迭代方法。