The definition of derived set calculation can be obtained according to the closure of set and the characteristics of derived set.

根据导集的性质以及闭包运算的定义，得到导集运算的定义。

youdao

Similar to the building of topological Spaces through the calculation of a closure of set, the topological Spaces can also be built through the derived set calculation.

又类似于从闭包运算出发建立拓扑空间，从而得到了从导集运算出发建立的拓扑空间。

youdao

The equivalence relation defined by the (transitive closure of the) set of imposed constraints implies N L = N L

实施的约束集合（的传递封包）所定义的等价关系表明：N L = N L

youdao

Fan David Stockdale described the closure of BarrysWorld as "the biggest set-back this community has ever seen".

BBC: Game over for BarrysWorld

Deloitte said no fixed date had been set for the closure of the 66 identified stores, which would continue to trade in the meantime.

BBC: HMV announces 66 store closures

It is understood there was no official contract, but an email shown to BBC Radio Stoke reveals that a date was set for the closure of the Burslem pool and the announcement of the Waterworld discounts.

BBC: Dimensions