论文标题
自然逻辑引导自回旋的多跳文档检索以进行事实验证
Natural Logic-guided Autoregressive Multi-hop Document Retrieval for Fact Verification
论文作者
论文摘要
事实验证的一个关键组成部分是从多个文档中进行的检索。最近的方法使用密集的表示,并在先前检索的文档上检索每个文档的检索。后一个步骤是在集合中的所有文档上执行的,需要将其密集的表示形式存储在索引中,从而产生高内存足迹。一个替代范式是检索和示范,其中使用诸如BM25之类的方法检索文档,其句子被重新掌握,并根据这些句子进行了进一步的文档,从而减少了内存要求。但是,这种方法可以脆弱,因为它们依靠启发式方法并在文档之间进行超链接。我们提出了一种用于多跳检索的新型检索方法,该方法由一个猎犬组成,该方法由一个回猎商组成,该检索器在知识源中共同评分文档和先前检索文档的句子,并使用自回旋配方从前检索的文档中进行句子,并由基于自然逻辑的证明系统指导,如果证据不足,则可以动态终止检索过程。该方法具有当前有关发烧,悬停和发烧的最新方法的竞争力,而使用$ 5 $至$ 10 $ $ 10 $ $ 10的记忆力比竞争系统少倍。对对抗数据集的评估表明,与常见的基于阈值的方法相比,我们方法的稳定性提高了。最后,与单独使用证据相比,证明系统可以帮助人类正确预测模型决策。
A key component of fact verification is thevevidence retrieval, often from multiple documents. Recent approaches use dense representations and condition the retrieval of each document on the previously retrieved ones. The latter step is performed over all the documents in the collection, requiring storing their dense representations in an index, thus incurring a high memory footprint. An alternative paradigm is retrieve-and-rerank, where documents are retrieved using methods such as BM25, their sentences are reranked, and further documents are retrieved conditioned on these sentences, reducing the memory requirements. However, such approaches can be brittle as they rely on heuristics and assume hyperlinks between documents. We propose a novel retrieve-and-rerank method for multi-hop retrieval, that consists of a retriever that jointly scores documents in the knowledge source and sentences from previously retrieved documents using an autoregressive formulation and is guided by a proof system based on natural logic that dynamically terminates the retrieval process if the evidence is deemed sufficient. This method is competitive with current state-of-the-art methods on FEVER, HoVer and FEVEROUS-S, while using $5$ to $10$ times less memory than competing systems. Evaluation on an adversarial dataset indicates improved stability of our approach compared to commonly deployed threshold-based methods. Finally, the proof system helps humans predict model decisions correctly more often than using the evidence alone.