Closure
这个词在阅读过程中经常碰到，本文对它进行总结。
“closure"是”close“的名词形式。
wikipedia Closure (mathematics)
A set is closed under an operation if performance of that operation on members of the set always produces a member of that set.
Examples
wikipedia Closure (computer programming)
wikipedia Kleene star
Transitive_closure
wikipedia Transitive_closure
Draft
有必要对closure进行总结，需要将它总结到graph章节中。
TensorFlow: Large-Scale Machine Learning on Heterogeneous Distributed Systems
下面的文章中提及了**closure：**
TensorFlow: Large-Scale Machine Learning on Heterogeneous Distributed Systems
the TensorFlow implementation can compute the transitive closure of all nodes that must be executed in order to compute the outputs that were requested
Draft 2
在 https://cwiki.apache.org/confluence/display/ZOOKEEPER/PoweredBy 中也是用了transitive closure这个词语
20201123
重复运用一个relation，从而形成一条path。
20201223
- 在龙书中有关于闭包的描述
- 在离散数学的关系章节中有闭包的描述
- Kleene star
- Context-free grammar中也有关于closure的描述
- 从Formation rule/Production rule的角度来看待闭包
- 从逻辑学推导的角度来看待闭包
我一直想要搞清楚的closure就是基于逻辑推导和集合论的。
Set theory是数学的基石所在，很多其他数学学科都是建立在它的基础之上。