An efficient algorithm for positive realizations
  We observe that successive applications of known results from the theory of positive systems lead to an {\it efficient general algorithm} for positive realizations of transfer functions. We give two examples to illustrate the algorithm, one of which complements an earlier result of \cite{large}. Finally, we improve a lower-bound of \cite{mn2} to indicate that the algorithm is indeed efficient in general. 
Wojciech Czaja (WROCLAW, Maryland), Philippe Jaming (MAPMO), Mat\'e   Matolcsi (RENYI Institute)