Theory of Lie groups

The theory of Lie groups is a branch of mathematics that studies continuous symmetry through the use of a special class of groups called Lie groups. A Lie group is a group that is also a differentiable manifold, which means that it has both algebraic structure (satisfying the group axioms) and geometric structure (allowing for the concepts of calculus to be applied). Lie groups are named after the Norwegian mathematician Sophus Lie, who developed this theory in the 19th century.