The Maurer–Cartan Form

This chapter illustrates the Maurer-Cartan form. On every Lie group G with Lie algebra g, there is a unique canonically defined left-invariant g-valued 1-form called the Maurer-Cartan form. The chapter describes the Maurer-Cartan form and the equation it satisfies, the Maurer-Cartan equation. The Maurer-Cartan form allows one to define a connection on the product bundle M × G → M for any manifold M. The Lie algebra g of a Lie group G is defined to be the tangent space at the identity. One will often identify the two vector spaces and think of elements of g as left-invariant vector fields on G.