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about: Research mathematician, category theory, universal algebra, semirings & semimodules, formalized mathematics, Lean theorem proving

: Research mathematician : category theory : universal algebra : semirings & semimodules : formalized mathematics : Lean theorem proving :

now

now: July 2026 — Kourovka Notebook preprint, May 2025 — Lean4 formalization (part-time), March 2025 — AMC/AIME Lean4 labeling, August 2024 — Weekly category seminars

:: July 2026 — Kourovka Notebook preprint :: May 2025 — Lean4 formalization (part-time) :: March 2025 — AMC/AIME Lean4 labeling :: August 2024 — Weekly category seminars ::

affiliations

affiliations: Harmonic, Project Numina, University of Cape Town, University of the Witwatersrand, Kili Technology, Lean Prover community, SAMS

::: Harmonic ::: Project Numina ::: University of Cape Town ::: University of the Witwatersrand ::: Kili Technology ::: Lean Prover community ::: SAMS :::

Group theory

Tarski's automorphisms

14 Nov 2024

Notes on Tarski’s proposal that logical notions are those invariant under every automorphism of the universe of discourse.

© 2026 Elias Judin