diff --git a/info4/kapitel-0/Mengentheorie.ipynb b/info4/kapitel-0/Mengentheorie.ipynb
index 96767457f52c7aa03427f82263223f3af0701ea5..3e5d2a5f07a46facb29de7f756ebfb9cf9919f31 100644
--- a/info4/kapitel-0/Mengentheorie.ipynb
+++ b/info4/kapitel-0/Mengentheorie.ipynb
@@ -545,7 +545,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Ein Theorem\n",
+    "# Ein Theorem (Distributivgesetz 1)\n",
     "\n",
     "Für alle Mengen $x$, $y$, $z$ gilt:\n",
     "* $x \\cup (y \\cap z) = (x\\cup y) \\cap (x\\cup z)$\n",
@@ -599,6 +599,148 @@
     "({2,3,55}∪{2,44,77})∩({2,3,55}∪{2,44,66})"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Beweis von  $x \\cup (y \\cap z) = (x\\cup y) \\cap (x\\cup z)$\n",
+    "\n",
+    "Lemmata:\n",
+    "1.  $x \\cup y = \\{a \\mid a\\in x \\vee a\\in y\\}$\n",
+    "2.  $x \\cap y = \\{a \\mid a\\in x \\wedge a\\in y\\}$\n",
+    "3.  $a \\in \\{b \\mid P(b)\\} \\equiv P(a)$\n",
+    "4.  $\\phi \\vee (\\psi \\wedge \\rho) \\equiv (\\phi \\vee \\psi) \\wedge (\\phi \\vee \\rho)$\n",
+    "\n",
+    "Äquivalenzbeweis \n",
+    "1.  $x \\cup (y \\cap z)$\n",
+    "2. (Lemma 1) $\\Longleftrightarrow$ $\\{a \\mid a\\in x \\vee a\\in (y \\cap z)\\}$ \n",
+    "3. (Lemma 2) $\\Longleftrightarrow$ $\\{a \\mid a\\in x \\vee a\\in \\{b \\mid b\\in y \\wedge b\\in z\\} \\}$ \n",
+    "4. (Lemma 3) $\\Longleftrightarrow$ $\\{a \\mid a\\in x \\vee (a\\in y \\wedge a\\in z) \\}$\n",
+    "5. (Lemma 4) $\\Longleftrightarrow$ $\\{a \\mid (a\\in x \\vee a\\in y) \\wedge (a\\in x \\vee a\\in z) \\}$\n",
+    "6. (Lemma 3, $\\Leftarrow$) $\\Longleftrightarrow$ $\\{a \\mid a\\in \\{b \\mid b\\in x \\vee b\\in y\\}  \\wedge a\\in \\{b \\mid b\\in x \\vee b\\in z\\} \\}$\n",
+    "7. (Lemma 1, $\\Leftarrow$) $\\Longleftrightarrow$ $\\{a \\mid a\\in x \\cup y \\wedge a\\in x \\cup z) \\}$\n",
+    "8. (Lemma 2, $\\Leftarrow$) $(x\\cup y) \\cap (x\\cup z)$"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Gesetze\n",
+    "\n",
+    "Für alle Mengen $x$, $y$, $z$ gilt:\n",
+    "* $x \\cup y = y \\cup x$  (Kommutativ 1)\n",
+    "* $x \\cap y = y \\cap x$  (Kommutativ 2)\n",
+    "* $x \\cup (y \\cup z) = (x\\cup y) \\cup z$  (Assoziativ 1)\n",
+    "* $x \\cap (y \\cap z) = (x\\cap y) \\cap z$  (Assoziativ 2)\n",
+    "* $x \\cup (y \\cap z) = (x\\cup y) \\cap (x\\cup z)$  (Distributiv 1, siehe oben)\n",
+    "* $x \\cap (y \\cup z) = (x\\cap y) \\cup (x\\cap z)$  (Distributiv 2)\n",
+    "* $z \\setminus (x \\cup y) = (z\\setminus x) \\cap (z\\setminus y)$  (De Morgan 1)\n",
+    "* $z \\setminus (x \\cap y) = (z\\setminus x) \\cup (z\\setminus y)$  (De Morgan 2)\n",
+    "* $x \\cup \\emptyset = x$  (Leere Menge 1)\n",
+    "* $x \\cap \\emptyset = \\emptyset$  (Leere Menge 2)\n",
+    "* $x \\cap (z \\setminus x) = \\emptyset$  (Leere Menge 3)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "$\\{1,3,7,9\\}$"
+      ],
+      "text/plain": [
+       "{1,3,7,9}"
+      ]
+     },
+     "execution_count": 31,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "(1..10) \\ ({2,4,6,8} ∪ {5,10})  // De Morgan 1 - linke Seite"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "$\\{1,3,5,7,9,10\\}$"
+      ],
+      "text/plain": [
+       "{1,3,5,7,9,10}"
+      ]
+     },
+     "execution_count": 28,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "(1..10) \\ {2,4,6,8}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "$\\{1,2,3,4,6,7,8,9\\}$"
+      ],
+      "text/plain": [
+       "{1,2,3,4,6,7,8,9}"
+      ]
+     },
+     "execution_count": 29,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "(1..10) \\ {5,10}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 32,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "$\\{1,3,7,9\\}$"
+      ],
+      "text/plain": [
+       "{1,3,7,9}"
+      ]
+     },
+     "execution_count": 32,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "((1..10) \\ {2,4,6,8}) ∩ ((1..10) \\ {5,10})  // De Morgan 1 - rechte Seite"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Gesetze von De Morgan:  $Op1(  x  ~ Op2 ~   y)$  wird umgewandelt nach $Op1(x) ~ Op2' ~ Op1(y)$, wo Op2' der duale Operator von Op2 ist."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
diff --git a/info4/kapitel-0/img/Venn.pdf b/info4/kapitel-0/img/Venn.pdf
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