Syntactic analysis plays an important role in semantic parsing, but the nature of this role remains a topic of ongoing debate. The debate has been constrained by the scarcity of empirical comparative studies between syntactic and semantic schemes, which hinders the development of parsing methods informed by the details of target schemes and constructions. We target this gap, and take Universal Dependencies (UD) and UCCA as a test case. After abstracting away from differences of convention or formalism, we find that most content divergences can be ascribed to: (1) UCCA's distinction between a Scene and a non-Scene; (2) UCCA's distinction between primary relations, secondary ones and participants; (3) different treatment of multi-word expressions, and (4) different treatment of inter-clause linkage. We further discuss the long tail of cases where the two schemes take markedly different approaches. Finally, we show that the proposed comparison methodology can be used for fine-grained evaluation of UCCA parsing, highlighting both challenges and potential sources for improvement. The substantial differences between the schemes suggest that semantic parsers are likely to benefit downstream text understanding applications beyond their syntactic counterparts.
翻译:合成分析在语义区分方面起着重要作用,但这一作用的性质仍然是一个持续辩论的议题。辩论由于合成和语义计划之间缺乏经验性比较研究而受到限制。这种研究阻碍根据目标计划和构造的细节制定分解方法。我们针对这一差距,并将普遍依赖和UCCA作为试验案例。我们从公约或形式主义差异中抽取出来后发现,大部分内容差异可归因于:(1) 化学协会理事会区分一个景点和非色;(2) 化学协会区分主要关系、次要关系和参与者;(3) 对多字表达的不同处理,以及(4) 不同对待不同语义联系。我们进一步讨论这两种计划采取明显不同做法的长尾情况。最后,我们表明,拟议的比较方法可用于对化学理事会区分进行细微评价,突出挑战和潜在的改进来源。各种计划之间的巨大差异表明,语义派分析师有可能超越其下游文本应用的受益性理解。