Luis Moraes | Searcharxiv

arXiv2017

Identifying Reference Spans: Topic Modeling and Word Embeddings help IR

The CL-SciSumm 2016 shared task introduced an interesting problem: given a document D and a piece of text that cites D, how do we identify the text spans of D being referenced by the piece of text? The shared task provided the first annotated dataset for studying this problem. We present an analysis of our continued work in improving our system's performance on this task. We demonstrate how topic models and word embeddings can be used to surpass the previously best performing system.

cs.CL↗

arXiv2016

Uniqueness of Normal Forms for Shallow Term Rewrite Systems

Uniqueness of normal forms ($UN^=$) is an important property of term rewrite systems. $UN^=$ is decidable for ground (i.e., variable-free) systems and undecidable in general. Recently it was shown to be decidable for linear, shallow systems. We generalize this previous result and show that this property is decidable for shallow rewrite systems, in contrast to confluence, reachability and other properties, which are all undecidable for flat systems. Our result is also optimal in some sense, since we prove that the $UN^=$ property is undecidable for two classes of linear rewrite systems: left-flat systems in which right-hand sides are of depth at most two and right-flat systems in which left-hand sides are of depth at most two.

cs.LO↗