tex improvements

vim/ftplugin/tex.vim

@@ -20,3 +20,6 @@ set conceallevel=0
 " spell checking
 set spell
 set spell spelllang=de
+
+" set textwidth for automatic line wrap
+set tw=80

vim/neosnippets/tex.snip

@@ -11,3 +11,15 @@ options     head
     \begin{align${1:#:options}}
         ${0}
     \end{align$1}
+
+snippet     sum
+abbr        sum
+options     head
+    \sum_{${0}}^{${1}}
+
+snippet     satz
+abbr        satz
+options     head
+    \begin{satz}
+        ${0}
+    \end{satz}