From 90b4d9b894494bc0b9f9f01644a0086713c6d354 Mon Sep 17 00:00:00 2001 From: Adrian Kummerlaender Date: Mon, 13 Mar 2017 21:28:08 +0100 Subject: Add section on Lebesgue's dominated convergence theorem --- content/analysis_3.tex | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/content/analysis_3.tex b/content/analysis_3.tex index 60f1825..c9194c0 100644 --- a/content/analysis_3.tex +++ b/content/analysis_3.tex @@ -387,3 +387,15 @@ Konvergiert $f_n$ fast überall gegen messbares $f : X \to [0,\infty]$, dann: $$\int_X f d\mu \leq \liminf_{n \to \infty} \int_X f_n d\mu$$ \subsection*{Majorisierte Konvergenz (Lebesgue)} + +Sei $f, f_n : X \to \overline\R$ messbar und $g : X \to [0,\infty]$ integrierbar. Konvergiere $(f_n)$ in $\overline\R$ f.ü. gegen $f$ und $\forall n \in \N : |f_n| \leq g$ f.ü. + +Dann sind $f$ und $f_n$ für alle $n \in \N$ integrierbar und: + +\vspace{-4mm} +\begin{align*} + \lim_{n \to \infty} \int_X f_n d\mu &= \int_X f d\mu \\ + |\int_X f_n d\mu - \int_X f d\mu| &\leq \int_{X \setminus N} |f_n - f| d\mu \to 0 +\end{align*} + +Mit $N := \{|f| = \infty\} \cup \cup_{n \in \N} \{|f_n| = \infty\}$ Nullmenge. -- cgit v1.2.3