arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1102.3253math.GNmath.FA
收藏

Borel类在开$LC$函数下的保持性

Preservation of the Borel class under open-$LC$ functions

Alexey Ostrovsky

摘要:

设$X$是加法类或乘法类$α,$的Cantor集\textbf{C}的Borel子集,$f: X \to Y$是点在$Y \subset \textbf{C}.$上具有紧原像的连续函数,若每个闭集$U$的像$f(U)$是开集与闭集的交,则$Y$是同一类的Borel集.这一结果推广了开函数和闭函数的类似结果。

英文摘要:

Let $X$ be a Borel subset of the Cantor set \textbf{C} of additive or multiplicative class $α,$ and $f: X \to Y$ be a continuous function with compact preimages of points onto $Y \subset \textbf{C}.$ If the image $f(U)$ of every clopen set $U$ is the intersection of an open and a closed set, then $Y$ is a Borel set of the same class. This result generalizes similar results for open and closed functions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑