(January 23, 1862 – February 14, 1943)
Famous for his Hilbert Spaces, David Hilbert is second only to Henri Poincaré when it comes to the greatest mathematicians who lived into the 20th century. (My research inferred that Alexander Grothendieck ranks above all who were born in 20th century). Hilbert made game-changing discoveries in many areas, including: Functional Analysis, Invariant Theory, and Axiomatic Theory. On the sphere of influence, very few mathematicians compare to him. As a dedicated professor, he mentored many renowned students such as Hermann Weyl, John von Neumann, and Emanuel Lasker. He also encouraged Emmy Noether; and supported Georg Cantor when math-heavyweights like Poincaré, Weyl and Kronecker opposed his Set Theory. Unable to stop the Nazis from dismissing and persecuting Jewish scientists and mathematicians in the 1930s, Hilbert assisted them in the best way he could: by giving them favorable references which helped them in getting jobs overseas. He also collaborated with Albert Einstein in developing what became known as the Einstein-Hilbert Action, (a precursor for the Einstein Field Equations in General Relativity). His contributions to algebra are far-reaching and remarkable. Many have been applied to both computing and mathematical physics. Also, his geometrical axioms were able to replace the Euclidean inventions which have been used for over 2000 years. Beloved and respected, David Hilbert is undoubtedly one of the most influential mathematicians ever.