Discrete Optimization for Unsupervised Sentence Summarization with Word-Level Extraction
Table 4: Ablation study of the search objective. Model HC_title_10 on the headline generation test set. Length constraint term omitted from notation.
['[BOLD] Objective  [ITALIC] f=', '[BOLD] Rouge\xa0F1 scores  [BOLD] R-1', '[BOLD] Rouge\xa0F1 scores  [BOLD] R-2', '[BOLD] Rouge\xa0F1 scores  [BOLD] R-L']
Search Objective. It shows that both language fluency and semantic similarity play a role in measuring the quality of a summary. The bi-directional language model is also slightly better than a uni-directional language model.