Albert Einstein (1879-1955) was a German-born scientist who made many contributions to the fields of Physics and Mathematics. Some of his mathematical discoveries are:
The theory of relativity
This theory is made up of two theories: theory of special relativity and general relativity. The theory of special relativity proved that the three laws of motion as given by Newton are only approximations which break when velocities approach light. The main result of this theory is Einstein’s famous mass-energy equivalence equation E = mc^2, which states that the energy E of a physical system is equal to the product of its mass (m) and the speed of light (c) squared.
The theory of general relativity proved that the law of gravitation as given by Newton is an approximation which breaks in the presence of strong fields of gravity. It includes a set of ten equations generally called Einstein Field Equations (EFE) that explain the interaction of gravitation when spacetime is curved by mass and energy.
The photoelectric effect
In this theory, Einstein posits that light behaves more like a particle than a wave.
He also contributed to the field of statistical mechanics through papers written on the role of kinetic-molecular theory of heat in the movement of small particles suspended in liquids.