Complexity results for prefix grammars

Resolving an open problem of Ravikumar and Quan, we show that equivalence of prefix grammars is complete in PSPACE. We also show that membership for these grammars is complete in P (it was known that this problem is in P) and characterize the complexity of equivalence and inclusion for monotonic grammars. For grammars with several premises we show that membership is complete in EXPTIME and hard for PSPACE for monotonic grammars

Theoretical Informatics and Applications Will be set by the publisher Informatique Théorique et Applications COMPLEXITY RESULTS FOR PREFIX GRAMMARS

Abstract. Resolving an open problem of Ravikumar and Quan, we show that equivalence of prefix grammars is complete in PSPACE. We also show that membership for these grammars is complete in P (it was known that this problem is in P) and characterize the complexity of equivalence and inclusion for monotonic grammars. For grammars with several premises we show that membership is complete in EXPTIME and hard for PSPACE for monotonic grammars. 1991 Mathematics Subject Classification. 03D03, 68Q17, 68Q42, 68Q45. 1