Abstract
In this paper, we investigate operations in summary generation. In order to align a summary expression with the corresponding original expression in source text, we introduce an automated algorithm based on dependency structure of sentences. Our algorithm detects not only one-to-one sentence alignment, but also one-to-many sentence alignment. We apply the algorithm to human made natural summaries, and analyze the results of the alignment. As a result of the analysis, we find most of the summary expressions are kept their dependency structure in original sentences and confirm one of the operation called “sentence combination”, in which more than two source sentences are used to generate a summary sentence, plays an important role in summary generation. Furthermore, we characterize operations and paraphrasing that cover most summary generation.
