Functional classification study for mathematical formulas retrieval

Recently mathematical formula retrieval has become a hot research topic. The user requirements for mathematical formula retrieval vary widely in different application scenarios. In this paper we conduct a thorough analysis of the existing researches of mathematical formula retrieval and classify the functional requirements of the mathematical formula retrieval into eight types: Full Match, Partial Match, Semantic Match, Structural Match, Equivalent Match, Relative Calculation Match, Graph Match, and Combination Match. The connotations and denotations of the eight kinds of requirements are defined in this paper. Furthermore, we compare and analyze the current studies on mathematical formulas retrieval according to eight types of functional requirements. We finally give some suggestions on the potential technical improvements on mathematical formula retrieval.