1 files changed, 97 insertions, 0 deletions
diff --git a/buch/chapters/95-homologie/images/tetraeder.tex b/buch/chapters/95-homologie/images/tetraeder.tex
new file mode 100644
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+++ b/buch/chapters/95-homologie/images/tetraeder.tex
@@ -0,0 +1,97 @@
+%
+% tetraeder.tex
+%
+% (c) 2021 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
+%
+\documentclass[tikz]{standalone}
+\usepackage{times}
+\usepackage{amsmath}
+\usepackage{txfonts}
+\usepackage[utf8]{inputenc}
+\usepackage{graphics}
+\usetikzlibrary{arrows,intersections,math,calc}
+\usepackage{ifthen}
+\begin{document}
+
+\newboolean{showgrid}
+\setboolean{showgrid}{false}
+\def\breite{7}
+\def\hoehe{4}
+
+\begin{tikzpicture}[>=latex,thick]
+
+% Povray Bild
+\node at (0,0) {\includegraphics[width=8cm]{tetraeder.jpg}};
+
+% Gitter
+\ifthenelse{\boolean{showgrid}}{
+\draw[step=0.1,line width=0.1pt] (-\breite,-\hoehe) grid (\breite, \hoehe);
+\draw[step=0.5,line width=0.4pt] (-\breite,-\hoehe) grid (\breite, \hoehe);
+\draw                            (-\breite,-\hoehe) grid (\breite, \hoehe);
+\fill (0,0) circle[radius=0.05];
+}{}
+
+\def\knoten#1#2{
+	%\fill[color=white,opacity=0.5] #1 circle[radius=0.2];
+	\node at #1 {$#2$};
+}
+
+\knoten{(-2.2,-3.6)}{0};
+\knoten{( 3.3,-1.9)}{1};
+\knoten{(-3.4,-1.2)}{2};
+\knoten{(-0.75,3.6)}{3};
+
+\def\s{0.2}
+
+\def\kante#1#2{
+	%\fill[color=white,opacity=0.5] #1 circle[radius=0.2];
+	\fill[color=white,opacity=0.5] 
+		($#1+(-\s,-\s)$) --
+		($#1+(+\s,-\s)$) --
+		($#1+(+\s,+\s)$) --
+		($#1+(-\s,+\s)$) -- cycle;
+	\node at #1 {$#2$};
+}
+
+\kante{(0.5,-2.8)}{k_0}
+\kante{(-2.8,-2.3)}{k_1}
+\kante{(-1.4,0)}{k_2}
+\kante{(-0.4,-1.55)}{k_3}
+\kante{(1.25,0.95)}{k_4}
+\kante{(-2.08,1.1)}{k_5}
+
+\def\r{0.33}
+
+\def\flaeche#1#2{
+	\fill[color=white,opacity=0.5]
+		($#1+({-\r*cos(30)},{-\r*sin(30)})$) --
+		($#1+({\r*cos(30)},{-\r*sin(30)})$) --
+		($#1+(0,{\r})$) -- cycle;
+	\node at #1 {$#2$};
+}
+
+\flaeche{(-0.7,-5)}{f_0}
+\draw (-0.7,-4.7) -- (-0.7,-3.25);
+\draw[->,color=black!70] (-0.7,-3.06) -- (-0.7,-2.5);
+\flaeche{(0.2,-0.5)}{f_1}
+\flaeche{(-2.3,-0.7)}{f_2}
+\coordinate (A) at (1,2.6);
+\coordinate (B) at (0,1);
+
+\flaeche{($1.2*(A)-0.2*(B)$)}{f_3}
+
+\def\t{0.58}
+\pgfmathparse{1-\t}
+\xdef\T{\pgfmathresult}
+\draw (A) -- ($\t*(A)+\T*(B)$);
+
+\def\t{0.48}
+\pgfmathparse{1-\t}
+\xdef\T{\pgfmathresult}
+\draw[->,color=black!70] ($\t*(A)+\T*(B)$) -- (B);
+
+
+\end{tikzpicture}
+
+\end{document}
+