Hubiness, length, crossings and their relationships in dependency trees
نویسنده
چکیده
Here tree dependency structures are studied from three different perspectives: their degree variance (hubiness), the mean dependency length and the number of dependency crossings. Bounds that reveal pairwise dependencies among these three metrics are derived. Hubiness (the variance of degrees) plays a central role: the mean dependency length is bounded below by hubiness while the number of crossings is bounded above by hubiness. Our findings suggest that the online memory cost of a sentence might be determined not just by the ordering of words but also by the hubiness of the underlying structure. The 2 moment of degree plays a crucial role that is reminiscent of its role in large complex networks.
منابع مشابه
Are crossing dependencies really scarce?
The syntactic structure of a sentence can be modelled as a tree, where vertices correspond to words and edges indicate syntactic dependencies. It has been claimed recurrently that the number of edge crossings in real sentences is small. However, a baseline or null hypothesis has been lacking. Here we quantify the amount of crossings of real sentences and compare it to the predictions of a serie...
متن کاملRandom crossings in dependency trees
It has been hypothesized that the rather small number of crossings in real syntactic dependency trees is a side-effect of pressure for dependency length minimization. Here we answer a related important research question: what would be the expected number of crossings if the natural order of a sentence was lost? We show that this number depends only on the number of vertices of the dependency tr...
متن کاملScarcity of crossing dependencies: A direct outcome of a specific constraint?
The structure of a sentence can be represented as a network where vertices are words and edges indicate syntactic dependencies. Interestingly, crossing syntactic dependencies have been observed to be infrequent in human languages. This leads to the question of whether the scarcity of crossings in languages arises from an independent and specific constraint on crossings. We provide statistical e...
متن کاملOn the Expressiveness of Information Extraction Patterns
Many recently reported machine learning approaches to the acquisition of information extraction (IE) patterns have used dependency trees as the basis for their pattern representations (Yangarber et al., 2000a; Yangarber, 2003; Sudo et al., 2003; Stevenson and Greenwood, 2005). While varying results have been reported for the resulting IE systems little has been reported about the ability of dep...
متن کاملThe influence of Chunking on Dependency Crossing and Distance
This paper hypothesizes that chunking plays important role in reducing dependency distance and dependency crossings. Computer simulations, when compared with natural languages, show that chunking reduces mean dependency distance (MDD) of a linear sequence of nodes (constrained by continuity or projectivity) to that of natural languages. More interestingly, chunking alone brings about less depen...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- CoRR
دوره abs/1304.4086 شماره
صفحات -
تاریخ انتشار 2013