  Digital mathematical libraries (DMLs) such as arXiv, Numdam, and EuDML
contain mainly documents from STEM fields, where mathematical formulae are
often more important than text for understanding. Conventional information
retrieval (IR) systems are unable to represent formulae and they are therefore
ill-suited for math information retrieval (MIR). To fill the gap, we have
developed, and open-sourced the MIaS MIR system. MIaS is based on the full-text
search engine Apache Lucene. On top of text retrieval, MIaS also incorporates a
set of tools for preprocessing mathematical formulae. We describe the design of
the system and present speed, and quality evaluation results. We show that MIaS
is both efficient, and effective, as evidenced by our victory in the NTCIR-11
Math-2 task.
