Fix compilation errors cause by updates

LinAlg2.tex

@@ -8,14 +8,14 @@
 \usepackage{amssymb}
 \usepackage{marvosym}
 \usepackage{mathtools}
-\usepackage[colorlinks=true, linkcolor=magenta]{hyperref}
 \usepackage{cancel}
 \usepackage[ngerman]{babel}
 \usepackage{harpoon}
 \usetikzlibrary{tikzmark,calc,arrows,arrows.meta,angles,math,decorations.markings}
 \usepackage{pgfplots}
 \usepackage{framed}
-\usepackage[hyperref,amsmath,amsthm,thmmarks,thref,framed]{ntheorem}
+\usepackage[hyperref,amsmath,thmmarks,thref,framed]{ntheorem}
+\usepackage[colorlinks=true, linkcolor=magenta]{hyperref}
 \usepackage{tcolorbox}
 \usepackage{geometry}
 \geometry{a4paper, top=35mm, left=25mm, right=25mm, bottom=30mm}
@@ -39,6 +39,13 @@
 \newcommand\K{\ensuremath{\mathbb{K}}}
 \newcommand\mapsfrom{\rotatebox{180}{$\mapsto$}}
 
+\theoremsymbol{\ensuremath{\square}}
+\theorembodyfont{\normalfont}
+\theoremheaderfont{\normalfont\it}
+\theoremseparator{.}
+\newtheorem*{proof}{Beweis}
+\qedsymbol{\Lightning}
+
 \definecolor{pastellblau}{HTML}{5BCFFA}
 \definecolor{pastellrosa}{HTML}{F5ABB9}
 \definecolor{weiss}{HTML}{FFFFFF}
@@ -50,6 +57,7 @@
 \theorembodyfont{\normalfont}
 \theoreminframepreskip{0em}
 \theoreminframepostskip{0em}
+\theoremsymbol{}
 \newtcbox{\theoremBox}{colback=pastellrosa!17,colframe=pastellrosa!87,boxsep=0pt,left=7pt,right=7pt,top=7pt,bottom=7pt}
 \def\theoremframecommand{\theoremBox}
 
@@ -1095,8 +1103,8 @@ $\le\genfrac{}{}{0pt}{0}{\dim(V)}{n}$, da
 					\text{\ref{eq:2.2.10.3}} - \text{\ref{eq:2.2.10.2}}
 					 & \implies \underbrace{(\lambda_r - \lambda_1)}_{\neq0} \mu_1 v_1 + \cdots +
 					\underbrace{(\lambda_r - \lambda_{r-1})}_{\neq0} \mu_{r-1} v_{r-1} = 0        \\
-					 & \implies v_1, \dots, v_{r-1} \text{ linear abhängig. \Lightning}
-				\end{aligned} \]
+					 & \implies v_1, \dots, v_{r-1} \text{ linear abhängig.}
+				\end{aligned} \]\qed
 	\end{itemize}
 \end{proof}
 
@@ -1749,7 +1757,7 @@ Angenommen \(\alpha - \lambda \id: V \to V\) nilpotent. Dann besitzt \(\alpha\)
 	Angenommen $\exists l\ge k$ mit $V_{l+1} \neq V_l$. Sei $0\neq v\in V_{l+1} \setminus V_l$
 	$\implies 0 = \alpha^{l+1}(v) = \alpha^{k+1}(\alpha^{l-k}(v))$ und $0\neq \alpha^l(v)
 		= \alpha^k (\alpha^{l-k}(v)) \implies 0\neq \alpha^{l-k}(v) \in V_{k+1}\setminus V_k$
-	\Lightning
+	\qed
 \end{proof}
 
 \begin{defin}