Mathematics_for_Physicists/chapters/sections/contents_measures.tex
2021-03-29 21:48:35 +02:00

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% !TeX root = ../../script.tex
\documentclass[../../script.tex]{subfiles}
\begin{document}
\section{Contents and Measures}
\begin{defi}
A set $M$ is said to be countable if there exists a surjective mapping from $\natn$ to $M$, i.e.
\[
\exists \seq{x} \subset M: ~~\forall y \in M ~\exists n \in \natn: ~~x_n = y
\]
A set $M$ is said to be countably infinite if it is countable and unbounded.
\end{defi}
\end{document}