@InProceedings{PrusaMIS2004,
  UPDATE  = { 2010-02-18 },
  author =      {Daniel Pr{\r u}{\v s}a},
  title =       {Two-dimensional Grammars in Context-free Form: Undecidability of the Emptiness Problem},
  year =        {2004},
  pages =       {104-114},
  booktitle =   {Proceedings of Mal{\' y} Informatick{\' y} Semin{\' a}{\v r} '04},
  editor =      {David Obdr{\v z}{\' a}lek and Jana {\v S}tanclov{\' a}},
  publisher =   {Matfyzpress},
  address =     {Prague, Czech Republic},
  isbn =        {80-86732-36-3},
  book_pages =  {150},
  month =       {January},
  day =         {17-24},
  venue =       {Josef{\r u}v D{\r u}l, Czech Republic},
  organization ={Faculty of Mathematics and Physics, Charles University},
  annote = {We present a generalization of context-free grammars to two dimensions and define
    picture languages generated by these grammars. Furthermore, we show that the
    emptiness problem is not decidable for the grammars. },
  keywords =    {two-dimensional grammars},
  prestige =    {local},
  authorship =  {100},
  project = { 300/2002/A-INF/MFF, GA CR 201/02/1456 },
  psurl = {[pdf, 181 KB]},
}