diff --git a/info4/kapitel-0/Logik.ipynb b/info4/kapitel-0/Logik.ipynb
index d45bf0aaa1e7791f7beab1148fddfff233a634f4..a9692f78a17eaacdc7eb3278eaa2d6fd27e399d6 100644
--- a/info4/kapitel-0/Logik.ipynb
+++ b/info4/kapitel-0/Logik.ipynb
@@ -829,6 +829,60 @@
     "                            NUND=bool((np=TRUE) ∧ (nq=TRUE))}"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Kontraposition\n",
+    "\n",
+    "$\\neg \\psi \\Rightarrow \\neg \\phi$ ist die Kontraposition von $\\phi \\Rightarrow \\psi$.\n",
+    "   \n",
+    "Ist diese Form äquivalent?\n",
+    "Zur Prüfung kann man die komplette Wahrheitstabelle aufbauen, mit allen möglichen Werten für die \"offenen\" Formeln $\\phi$, $\\psi$"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "|p|q|IMPL|KONT|np|nq|\n",
+       "|---|---|---|---|---|---|\n",
+       "|$\\mathit{FALSE}$|$\\mathit{FALSE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|\n",
+       "|$\\mathit{FALSE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{FALSE}$|\n",
+       "|$\\mathit{TRUE}$|$\\mathit{FALSE}$|$\\mathit{FALSE}$|$\\mathit{FALSE}$|$\\mathit{FALSE}$|$\\mathit{TRUE}$|\n",
+       "|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{TRUE}$|$\\mathit{FALSE}$|$\\mathit{FALSE}$|\n"
+      ],
+      "text/plain": [
+       "p\tq\tIMPL\tKONT\tnp\tnq\n",
+       "FALSE\tFALSE\tTRUE\tTRUE\tTRUE\tTRUE\n",
+       "FALSE\tTRUE\tTRUE\tTRUE\tTRUE\tFALSE\n",
+       "TRUE\tFALSE\tFALSE\tFALSE\tFALSE\tTRUE\n",
+       "TRUE\tTRUE\tTRUE\tTRUE\tFALSE\tFALSE\n"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    ":table {p,q,IMPL,KONT,np,nq| p:BOOL & q:BOOL & np = bool(¬(p=TRUE)) & nq = bool(¬(q=TRUE)) &\n",
+    "                            IMPL=bool(p=TRUE => q=TRUE) &\n",
+    "                            KONT=bool((nq=TRUE) => (np=TRUE))}"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Es gilt also:\n",
+    "$\\phi \\Rightarrow \\psi$ $\\equiv$ $\\neg \\psi \\Rightarrow \\neg \\phi$  ."
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},