• The Inria's Research Teams produce an annual Activity Report presenting their activities and their results of the year. These reports include the team members, the scientific program, the software developed by the team and the new results of the year. The report also describes the grants, contracts and the activities of dissemination and teaching. Finally, the report gives the list of publications of the year.

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## Section: New Results

### Dedukti

Frédéric Blanqui and Guillaume Genestier have formally defined the operational semantics of Dedukti 2.5, showing some problems with non left-linear rewrite rules.

Rodolphe Lepigre, Frédéric Blanqui and Franck Slama developed a new version of Dedukti , available on https://github.com/Deducteam/lambdapi, with meta-variables and a small set of tactics in order to be able to build Dedukti proofs interactively.

Aristomenis-Dionysios Papadopoulos has added a rewrite tactic in the style of Ssreflect [27].

Emilio Gallego added an LSP server for communicating with editors.

Ismail Lachheb has developed a plugin for Dedukti based on the LSP protocol into the Atom editor [25].

Guillaume Burel added support for polarized Deduction modulo theory in Dedukti .

Quentin Ye has developed an algorithm to compare $\lambda$-terms. The main point was to take sharing into account, so as to relate the complexity with the space used to represent the term, rather than with the size of the term. He has implemented this algorithm in the Dedukti codebase. He has also run his algorithm on examples that show an exponential speed-up compared to the naive algorithm [21].