The Complexity of Computing Maximal Word Functions

Maximal word functions occur in data retrieval applications and have connections with ranking problems, which in turn were rst investigated in relation to data compression 21 . By the maximalword function" of a language L  , we mean the problem of nding, on input x, the lexicographically largest word belonging to L that is smaller than or equal to x. In this paper we present a parallel algorithm for computing maximal word functions for languages recognized by one way nondeterministic auxiliary pushdown automata and hence for the class of context free languages. This paper is a continuation of a stream of research focusing on the problem of identifying properties others than membership which are easily computable for certain classes of languages. For a survey, see 24 . Subject classi cations. 68Q15,68Q25,68Q45.

• Type: Conference
• Year: 1991
• Where: FCT
• Authors: Danilo Bruschi, Giovanni Pighizzini
• Keywords: Applied Computing, Data Retrieval Applications, FCT 1991, Maximal Word Functions, Nondeterministic Auxiliary Pushdown