# 力学の基礎（その６）

現在２０２２年１月６日２０時３４分である。（この投稿は、ほぼ２０５８文字）

私の訳

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

位相空間 の１点 の開近傍とは、 となる開集合 である。同様に、 の部分集合 について、 の開近傍であるとは、 が開集合で、 となることである。

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

グーグル翻訳

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

原文スキャン後 で修正

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

An open neighborhood of a point in a topological space is an open set such that . Similarly, for a subset of , is an open neighborhood of if is open and .

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

で、 は、開集合なんだ。一方、 の方は、開集合でも閉集合でもない。そして、例えば、は、閉集合なんだ」

現在２０２２年１月６日２２時４７分である。おしまい。