Q: How to adjust the space between text in enumerate I would like to arrange the text in both brackets (sicheres Ereignis) and (unmögliches Ereignis) exactly among each other.
I tried to do it with tabbing, but it did not work. So I used hspace, but if you zoom in on the PDF you can see that it is not exact. This is what I have so far:
\documentclass{article}
\usepackage{enumitem}
\usepackage[T1]{fontenc}
\usepackage[german]{babel}
\usepackage{amssymb}


\begin{document}
 
\begin{enumerate}[label={\alph*)}]
  \item $A \cup \overline{A}=\Omega \in S$ \hspace{1.3cm} (sicheres Ereignis)
  \item {\O} $=\overline{\Omega} \in S$ \hspace{2cm} (unmögliches Ereignis)
\end{enumerate}

\end{document}

Is there a better and easier way to do it?
Thanks a lot

A: You can put the two formulas in a box of fixed width, though you need to guess the correct size; alternatively use a tabular. I'd use \varnothing from amssymb instead of \O, which is a text letter.
\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{enumitem}
\usepackage{amssymb}% for \varnothing

\begin{document}

See this
\begin{enumerate}[label={\alph*)}]
\item \makebox[3cm][l]{$A \cup \overline{A}=\Omega \in S$} (sicheres Ereignis)
\item \makebox[3cm][l]{$\varnothing=\overline{\Omega} \in S$} (unmögliches Ereignis)
\end{enumerate}
or maybe this\par\medskip\noindent
\begin{tabular}{lll}
a) & $A \cup \overline{A}=\Omega \in S$    & (sicheres Ereignis) \\[1ex]
b) & $\varnothing=\overline{\Omega} \in S$ & (unmögliches Ereignis)
\end{tabular}

\end{document}



A: A solution with eqparbox (may require two compilations). Its box commands use a tag rather than a length, and all boxes  sharing the same tag have the length of the widest contents. I took the opportunity to use the correct way to denote the empty set, with amssymb.
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[german]{babel}
\usepackage{amssymb}
\usepackage{enumitem}
\usepackage{eqparbox}

\begin{document}

\begin{enumerate}[label={\alph*)}]

\item\eqmakebox[M][l]{$A \cup \overline{A}=\Omega \in S$\qquad} (sicheres Ereignis)
\item \eqmakebox[M][l]{$\varnothing =\overline{\Omega} \in S$} (unmögliches Ereignis)

\end{enumerate}

\end{document} 


