Angle Bracket

The combination of a Bra and Ket (bra+ket = bracket) which represents the Inner Product of two functions or vectors,

$$\left\langle{f\vert g}\right\rangle{}=\int f(x)g(x)\,dx$$

$$\left\langle{{\bf v}\vert{\bf w}}\right\rangle{} = {\bf v}\cdot{\bf w}.$$

By itself, the Bra is a Covariant 1-Vector, and the Ket is a Covariant One-Form. These terms are commonly used in quantum mechanics.

See also Bra, Differential k-Form, Ket, One-Form