Artur Jez, Alexander Okhotin. On the Number of Nonterminal Symbols in Unambiguous Conjunctive Grammars. In Martin Kutrib, Nelma Moreira, Rogério Reis, editors, Descriptional Complexity of Formal Systems - 14th International Workshop, DCFS 2012, Braga, Portugal, July 23-25, 2012. Proceedings. Volume 7386 of Lecture Notes in Computer Science, pages 183-195, Springer, 2012. [doi]
Abstract is missing.