We present our method for tackling the legal case retrieval task of the
Competition on Legal Information Extraction/Entailment 2019. Our approach is
based on the idea that summarization is important for retrieval. On one hand,
we adopt a summarization based model called encoded summarization which encodes
a given document into continuous vector space which embeds the summary
properties of the document. We utilize the resource of COLIEE 2018 on which we
train the document representation model. On the other hand, we extract lexical
features on different parts of a given query and its candidates. We observe
that by comparing different parts of the query and its candidates, we can
achieve better performance. Furthermore, the combination of the lexical
features with latent features by the summarization-based method achieves even
better performance. We have achieved the state-of-the-art result for the task
on the benchmark of the competition.

采用编码总结、文档表示模型、词汇特征提取等方法，结合资源进行比较及潜在特征提取，实现针对法律信息提取 / 推理比赛的最优成果。