Intriguing sangaku

Father of set theory, Georg Cantor proves to be one of the pioneers of a reflection on the foundations of mathematics that will contribute to shifting the history of sciences. At the heart of conjectures, some of which are still unresolved today, sometimes rejected by mathematicians of his time, he will remain the man who sought to tame the infinite. Multiplicity of infinities, continuum hypothesis, unexpected relations between certain sets of numbers, sufficient conditions for there to exist bijections between two sets or, on the contrary, that there are none...\r\nCantor frenetically clears all the groundwork, sometimes making a few errors or being unable to explain certain paradoxes, but he opens the door to a new approach to the foundation of mathematics that will survive him for a long time!

The Japanese votive tablets found at the entrance of certain temples have long interested mathematicians because they sometimes contain elegant geometric puzzles, where circles play an important role. Their resolution is easy when it requires no particular result. More often, one must appeal to classical theorems, such as the Pythagorean theorem. Finally, in some rare cases, the problem posed has resisted for centuries… One cannot imagine it: the last puzzle was only solved in 2020! Welcome to the world of sangaku.