Tullio Levi-Civita, was an Italian mathematician, most famous for his work on absolute differential calculus and its applications to the theory of relativity, but who also made significant contributions in other areas. He was a pupil of Gregorio Ricci-Curbastro, the inventor of tensor calculus. His work included foundational papers in both pure and applied mathematics, celestial mechanics, analytic mechanics and hydrodynamics.

Gregorio Ricci-Curbastro was an Italian mathematician. He is most famous as the discoverer of tensor calculus.