网页3 个回答. 知乎用户. 先抄个书:. If X is any metric space, or more generally any topological space, the \sigma - algebra generated by the family of open sets in X is called the Borel \sigma - algebra on X and is denoted by B_X . Its members are called Borel sets. 不难看出,我们需要先解释 代数, \sigma - 代数,然后 ...