LERA (Locate, Explore, Retrace and Apprehend)

In the humanities, text comparison is essential for scholarly editing the traditions of a text with its different witnesses under study.

For the computer-aided creation of a critical apparatus, there have been established approaches and tools for many years. However, they mainly focus only on subsentences or sentences.

The LERA (Locate, Explore, Retrace and Apprehend complex text variants) working environment developed at the Institute for Computer Science of the Martin Luther University Halle-Wittenberg provides an efficient and easy-to-use automatic comparison of entire chapters or books. It is based on a two stage collation approach: an efficient, fully automatic alignment of text segments, which can be paragraphs, subparagraphs or sentences, with interactive post-processing options, followed by the detailed comparison at segment level.

LERA combines the entire process of document management, tokenization/segmentation, normalization, alignment, and visualization with interactive control options and exploratory tools. It has already been and is being successfully applied in a wide range of Digital Humanities projects of different languages, e.g. for Arabic, French, Hebrew as well as German and English texts.

List of editorial projects that use LERA (incomplete):

• Kalīla and Dimna – AnonymClassic. Prof. Dr. Beatrice Gründler, Seminar for Semitic and Arabic Studies, FU Berlin. Funded by a ERC Advanced Grant 2018-2023 and a DFG Leibniz Prize 2020-2027.
• Hannah Arendt. Kritische Gesamtausgabe. Long-term project of the German Research Foundation (DFG), since 2020.
• William Lovell Digital. Prof. Dr. Maximilian Bergengruen, Institute for German Language and Literature, University Würzburg. Funded by the German Research Foundation (DFG), 2024-2027.
• Material and Digital Advances in the Study of Manuscripts: Codex Vercellensis (VL 3) and Codex Sangallensis 1395 (Σ). Prof. Dr. Hubert Mara, Institute of Computational Ancient Studies, FU Berlin and Prof. Dr. Annette Weissenrieder, Institute of Biblical Studies, Martin Luther University Halle-Wittenberg. Funded by the German Research Foundation (DFG), 2025-2028.
• Rückerts Liebesfrühling Digital. Prof. Dr. Maximilian Bergengruen, Institute for German Language and Literature, University Würzburg. Funded by the German Research Foundation (DFG), 2026-2029.
• HyperAzpilcueta–Visualizing the Instability of Early Modern Normative Knowledge. Dr. Manuela Bragagnolo, Max Planck Institute for Legal History and Legal Theory, Frankfurt am Main.
• Guillaume Thomas François Raynal: Histoire philosophique et politique des établissements et du commerce des européens dans les deux indes. Interdisciplinary Centre for European Enlightenment Studies, Halle (Saale). Funded by the Federal Ministry of Education and Research (BMBF), 2012-2015.
• The bases of Slovenian narrative prose: A two-century tradition of Slovenian narrative prose from the mid-seventeenth to mid-nineteenth century. Andrejka Žejn, Slovenian Academy of Sciences and Arts, Ljubljana, 2021.
• Keter Shem Ṭov (“Crown of the Good Name”). Apl. Prof. Dr. Geold Necker, Seminar für Judaistik/Jüdische Studien, Martin Luther University Halle-Wittenberg. Funded by the German Research Foundation (DFG), 2019-2026.

If you would like to test LERA for an editing project, please contact us at: lera@uzi.uni-halle.de. We would be happy to provide you with your own instance of the latest developer version on our servers. The research environment is provided to you as a web-based service (Software as a Service).

As part of the interdisciplinary COMUTE project, funded by the DFG from 2024 to 2027, LERA is to be expanded to include the semi-automatic collation of multilingual versions of a text, which are not necessarily translations in the sense of a word-for-word and meaning-for-meaning transfer from a source language into a target language.

In addition to the LERA team, the Freie Universität Berlin (Prof. Dr. Frank Fischer, Dr. Brigitte Grote) and the University of Potsdam (Prof. Dr. Manfred Stede) are involved in the COMUTE project.