Gheorghe P un

Six nonterminals are enough for generating each r.e. language by a matrix grammar

Gheorghe P un, 1984 .

On the generative capacity of parallel communicating grammar systems

Arto Salomaa, Sorina Vicolov, Gheorghe P un, 1992 .

On some open problems about marcus contextual languages

Gheorghe P un, 1985 .

Normal forms for bicolored-digraph-grammar systems

Gheorghe P un, 1979 .