Which one is better: presentation-based or content-based math search?
  Mathematical content is a valuable information source and retrieving this content has become an important issue. This paper compares two searching strategies for math expressions: presentation-based and content-based approaches. Presentation-based search uses state-of-the-art math search system while content-based search uses semantic enrichment of math expressions to convert math expressions into their content forms and searching is done using these content-based expressions. By considering the meaning of math expressions, the quality of search system is improved over presentation-based systems. 
Minh-Quoc Nghiem, Giovanni Yoko Kristianto, Goran Topic, Akiko Aizawa
cs.IR