This tool is meant for students to practice writing mathematical proofs. Several background libraries for sets, relations and functions have been implemented such that you can directly start writing a proof.
Internally, the mathematical text is transformed into a sequence of first-order formulas. This representation implies certain proof obligations which are checked by Automated Theorem Provers. An overview of the inner workings is described in a preprint which will be presented at CSEDU 2018. A complete system description can be found here.
The tool itself is written in Haskell. If you want to learn more about the implementation, have a look at the source code.
You want to improve Elfe or implement new background libraries? You can get in touch via GitHub. If you want to do a larger project with Elfe, e.g., work on it in your thesis, you best get in touch with us at firstname.lastname@example.org.