Parallel on-line parsing in constant time per word

An on-line parser processes each word as soon as it is typed by the user, without waiting for the end of the sentence. Thus, in an interactive system, a sentence will be parsed almost immediately after the last word has been presented.

The complexity of an on-line parser is determined by the resources needed for the analysis of a single word, as it is assumed that previous words have been processed already. Sequential parsing algorithms like CYK or Earley need O(n²) time for the nth word. A parallel implementation in O(n) time on O(n) processors is straightforward. In this paper a novel parallel on-line parser is presented that needs O(1) time on O(n²) processors.