Conventional approaches to the construction of word vectors typically require very large amounts of unstructured text and powerful computing hardware, and the vectors themselves are also difficult if not impossible to inspect or interpret on their own. In this paper, we introduce a method for building word vectors using the framework of vector symbolic architectures in order to encode the semantic information in wordnets, such as the Open English WordNet or the Open Multilingual Wordnet. Such vectors perform surprisingly well on common word similarity benchmarks, and yet they are transparent, interpretable, and the information contained within them has a clear provenance.

This paper describes the design and evaluation of a system for the automatic detection and resolution of shell nouns in German. Shell nouns are general nouns, such as fact, question, or problem, whose full interpretation relies on a content phrase located elsewhere in a text, which these nouns simultaneously serve to characterize and encapsulate. To accomplish this, the system uses a series of lexico-syntactic patterns in order to extract shell noun candidates and their content in parallel. Each pattern has its own classifier, which makes the final decision as to whether or not a link is to be established and the shell noun resolved. Overall, about 26.2% of the annotated shell noun instances were correctly identified by the system, and of these cases, about 72.5% are assigned the correct content phrase. Though it remains difficult to identify shell noun instances reliably (recall is accordingly low in this regard), this system usually assigns the right content to correctly classified cases.

This article provides an extensive overview of the literature related to the phenomenon of non-nominal-antecedent anaphora (also known as abstract anaphora or discourse deixis), a type of anaphora in which an anaphor like “that” refers to an antecedent (marked in boldface) that is syntactically non-nominal, such as the first sentence in “It’s way too hot here. That’s why I’m moving to Alaska.” Annotating and automatically resolving these cases of anaphora is interesting in its own right because of the complexities involved in identifying non-nominal antecedents, which typically represent abstract objects such as events, facts, and propositions. There is also practical value in the resolution of non-nominal-antecedent anaphora, as this would help computational systems in machine translation, summarization, and question answering, as well as, conceivably, any other task dependent on some measure of text understanding.

Most of the existing approaches to anaphora annotation and resolution focus on nominal-antecedent anaphora, classifying many of the cases where the antecedents are syntactically non-nominal as non-anaphoric. There has been some work done on this topic, but it remains scattered and difficult to collect and assess. With this article, we hope to bring together and synthesize work done in disparate contexts up to now in order to identify fundamental problems and draw conclusions from an overarching perspective. Having a good picture of the current state of the art in this field can help researchers direct their efforts to where they are most necessary.

Because of the great variety of theoretical approaches that have been brought to bear on the problem, there is an equally diverse array of terminologies that are used to describe it, so we will provide an overview and discussion of these terminologies. We also describe the linguistic properties of non-nominal-antecedent anaphora, examine previous annotation efforts that have addressed this topic, and present the computational approaches that aim at resolving non-nominal-antecedent anaphora automatically. We close with a review of the remaining open questions in this area and some of our recommendations for future research.

This contribution involves the manual annotation of shell nouns and their antecedents in a multilingual context. Shell nouns are abstract nouns, which like pronouns are semantically incomplete and derive their meanings from other parts of a text to which they refer, often anaphorically. Unlike pronouns, shell nouns also serve to characterize the content to which they refer. The annotation schema we introduce allows for the annotation of shell nouns along with their content and their translation in a parallel text. This approach should enable the production of data on shell nouns which encompasses various aspects of their behavior that have not yet been investigated in detail, including the use of multiple content phrases, nominalized content phrases, plural shell nouns or crosslinguistic behavior.