https://en.wikipedia.org/wiki/Julia_Robinson

https://en.wikipedia.org/wiki/Henri_Poincar%C3%A9

https://en.wikipedia.org/wiki/Georg_Cantor

Nikolai Ivanovich Lobachevsky (Russian: Никола́й Ива́нович Лобаче́вский, IPA: [nʲikɐˈlaj ɪˈvanəvʲɪtɕ ləbɐˈtɕɛfskʲɪj] (listen); 1 December [O.S. 20 November] 1792 – 24 February [O.S. 12 February] 1856) was a Russian mathematician and geometer, known primarily for his work on hyperbolic geometry, otherwise known as Lobachevskian geometry, and also for his fundamental study on Dirichlet integrals, known as the Lobachevsky integral formula.

William Kingdon Clifford called Lobachevsky the “Copernicus of Geometry” due to the revolutionary character of his work.

https://en.wikipedia.org/wiki/Nikolai_Lobachevsky

János Bolyai (Hungarian: [ˈjaːnoʃ ˈboːjɒi]; 15 December 1802 – 27 January 1860) or Johann Bolyai, was a Hungarianmathematician, who developed absolute geometry—a geometry that includes both Euclidean geometry and hyperbolic geometry. The discovery of a consistent alternative geometry that might correspond to the structure of the universe helped to free mathematicians to study abstract concepts irrespective of any possible connection with the physical world.

https://en.wikipedia.org/wiki/J%C3%A1nos_Bolyai