Ket

A ket  is a vector living in a dual vector space to that containing bras . Bras and kets are commonly encountered in quantum mechanics. Bras and kets can be considered as 1-vectors and 1-forms (or vice versa), although this is almost always done only in a finite-dimensional vector space.
Considered as an inner product, the bra and ket form an angle bracket (bra+ket = bracket) .

SEE ALSO:Angle Bracket, Bra, Contravariant Vector, Covariant Vector, Differential k-Form, Inner Product, L2-Inner Product, One-Form

REFERENCES:

Dirac, P. A. M. "Bra and Ket Vectors." §6 in Principles of Quantum Mechanics, 4th ed. Oxford, England: Oxford University Press, pp. 16 and 18-22, 1982.

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