\title{Code Problems on Traces}


\author{Volker Diekert \qquad   Anca Muscholl\thanks{This research has
    been supported in part by the French-German research programme
    PROCOPE.} }

\institute{ Universit\"at Stuttgart, 
Institut f\"ur Informatik \\ Breitwiesenstr. 20-22,
 D-70565 Stuttgart }

\begin{abstract}
  The topic of codes in the framework of trace monoids leads to interesting and
  challenging decision problems of combinatorial flavour. We give an overview of
  the current state of some basic questions in this field. Among these, we
  consider the existence problem for strong codings, clique-preserving morphisms
  and the unique decipherability problem (code problem).
\end{abstract}