minimality meaning in English

极小性
最小性

Another problem of minimality also remains unsolved ? to wit , what is the smallest number of digits a puzzle maker can place in a starting grid and still guarantee a unique solution
另外还有一类极小的问题也还没有解决：在保证有唯一解的条件下，一个初盘至少需要几个数字？
According to the fact , we can give a minimal value of mtbf . when one value is smaller than the minimality , the relevant time may be thought of the theoretical lifetime of system
求出mtbf随时间的变化曲线，根据实际的情况设定一个最小的mtbf值，如果小于该值，那么对应的时间可认为是该系统的预计的理论寿命。