diff --git a/is/ub8/is8.pdf b/is/ub8/is8.pdf
index b952576..f3fd265 100644
--- a/is/ub8/is8.pdf
+++ b/is/ub8/is8.pdf
Binary files differ
diff --git a/is/ub8/is8.tex b/is/ub8/is8.tex
index 5929687..bc79c70 100644
--- a/is/ub8/is8.tex
+++ b/is/ub8/is8.tex
@@ -98,7 +98,8 @@
                 \item common ancestors can also be blocked
                 \item common descendants are not taken in the separation set
             \end{itemize}
-            Because the graph is acyclic each path belongs clearly to one of the above categories and so can be blocked.
+            Because the graph is acyclic each path belongs clearly to one of the above categories and so can be blocked.\\
+            \textcolor{red}{If nodes are not connected at all they're ``blocked'' by any set.}
         \end{itemize}
     \Aufgabe{IC}{25}\\
         \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto, node distance=2cm]
diff --git a/is/ub9/is9.pdf b/is/ub9/is9.pdf
index f03aa58..06362ac 100644
--- a/is/ub9/is9.pdf
+++ b/is/ub9/is9.pdf
Binary files differ
diff --git a/is/ub9/is9.tex b/is/ub9/is9.tex
index 69c20ec..08c5668 100644
--- a/is/ub9/is9.tex
+++ b/is/ub9/is9.tex
@@ -94,8 +94,8 @@
             \end{pmatrix}\begin{pmatrix}
             x\\y
             \end{pmatrix}= x^2+2xy+y^2=(x+y)^2 \geq 0 \forall{x,y}$\checkmark
-            \item $k(x,y) =xy\\
-             <x,y> \geq 0 \forall{x,y} $\checkmark
+            \item $k(x,y) =xy$\\
+             $<x,y>$ is a kernel according to lecture\checkmark
             \item No kernel $k(x,y) =\dfrac{1}{2}(x+y)\\
             k(-1,-1) =-1 \ngeq 0\\$
             But for a Kernel ist has to hold:\\