Coframe

Coframe

In mathematics, a coframe or coframe field on a smooth manifold M is a system of one-forms or covectors which form a basis of the cotangent bundle at every point. In the exterior algebra of M, one has a natural map from v_k:\bigoplus^kT^*M\to\bigwedge^kT^*M, given by v_k:(\rho_1,\ldots,\rho_k)\mapsto \rho_1\wedge\ldots\wedge\rho_k. If M is n dimensional a coframe is given by a section σ of \bigoplus^nT^*M such that v_n\circ\sigma\neq 0. The inverse image under vn of the complement of the zero section of \bigwedge^nT^*M forms a GL(n) principal bundle over M, which is called the coframe bundle.

See also