Measuring Closure Properties of Patent Sublanguages

Patent search is an important information retrieval problem in scientific and business research. Semantic search would be a large improvement to current technologies, but requires some insight into the language of patents. In this article we test the fit of the language of patents to the sublanguage model, focussing on closure properties. The research presented here is relevant to the topic of sublanguage identification for different domains, and to the study of the language of patents. We investigate the hypothesis that fit to the sublanguage model increases as one moves down the International Patent Classification hierarchy. The analysis employs a general English corpus and patent documents from the MAREC corpus. It is shown that patents generally fit the sublanguage model, with some variability between categories in the extent of the fit.