TY - JOUR AU - de Rauglaudre, Daniel PY - 2017/01/01 Y2 - 2024/03/28 TI - Formal Proof of Banach-Tarski Paradox JF - Journal of Formalized Reasoning JA - JFR VL - 10 IS - 1 SE - Articles DO - 10.6092/issn.1972-5787/6927 UR - https://jfr.unibo.it/article/view/6927 SP - 37 - 49 AB - Banach-Tarski Paradox states that a ball in 3D space is equidecomposable with twice itself, i.e. we can break a ball into a finite number of pieces, and with these pieces, build two balls having the same size as the initial ball. This strange result is actually a Theorem which was proven in 1924 by Stefan Banach and Alfred Tarski using the Axiom of Choice.We present here a formal proof in Coq of this theorem. ER -