Jannis Limperg
Member Of Technical Staff at Axiom
Munich, Bavaria, Germany
Summary
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Rockstar🎓
Top SchoolJannis Limperg is a Member of Technical Staff and formal methods researcher with 13 years of engineering experience, specializing in interactive theorem proving and dependently typed languages. He has worked on proof automation for Lean with Jasmin Blanchette’s group, contributed to Lean 4 and mathlib, and formalized deep results in Coq for the UniMath library, demonstrating comfort across Lean, Coq, Agda and Haskell. His industry roles include applied research on neurosymbolic AI at AWS and current work as a Lean expert at Axiom, bridging cutting‑edge theorem proving with practical tooling. Jannis combines rigorous mathematical foundations—evident in work on injective pairing and univalence—with hands‑on implementation, from binomial heaps in Lean 4 to tactic engineering in mathlib3. Based in Munich, he brings academic depth (PhD work across VU Amsterdam and LMU) and production experience to projects that demand both formal verification and pragmatic software development. Colleagues value his ability to turn abstruse proofs into maintainable code and reproducible automation.
13 years of coding experience
1 year of employment as a software developer
Bachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at The University of FreiburgMaster of Science - MS, Computer Science, Master of Science - MS, Computer Science at Chalmers University of Technology
Stackoverflow
643reputation
6kreached
11answers
2questions
Github Skills (22)
algorithms10
develop10
foundation10
proofs10
proof10
tactics10
automation10
coq10
theorem-proving10
automations10
functional-programming10
leanback10
coq-library9
math9
mathematics9
Programming languages (15)
Github contributions (5)
leanprover-community/mathlib3
Jan 2020 - Jun 2021
Lean 3's obsolete mathematical components library: please use mathlib4
Role in this project:
Back-end Developer
Back-end DeveloperContributions:27 reviews, 140 commits, 23 PRs in 1 year 4 months
Contributions summary:Jannis contributed to the Lean 3 mathematical components library, implementing and refactoring tactics related to formal proofs. Their work focused on improving existing tactics, such as `clear` and `rename`, to enhance their functionality and usability. The user also introduced a new tactic, `generalizes`, for generalizing over multiple expressions, facilitating proofs involving dependencies. Further contributions included adding monadic versions of list functions.
maththeorem-provingcomponents-librarymathematicsjavascript
leanprover/lean4
Aug 2021 - May 2022
Lean 4 programming language and theorem prover
Role in this project:Back-end Developer
Back-end DeveloperContributions:6 reviews, 15 commits, 14 PRs in 9 months
Contributions summary:Jannis primarily contributed to the `Std/Data/BinomialHeap.lean` file, focusing on implementing and refactoring the Binomial Heap data structure within the Lean 4 programming language. Their commits involved documenting the code, renaming constructors, optimizing functions like `head?`, and adding functionalities like `ofList` and `ofArray`. The user also addressed a specific bug related to the `BinomialHeap.insert` and `tail` operations.
dependent-typeshomotopy-type-theoryprovertheoremtheorem-prover
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