In mathematics, and more specifically in the theory of von Neumann algebras, a crossed product is a basic method of constructing a new von Neumann algebra from a von Neumann algebra acted on by a group. It is related to the semidirect product construction for groups. (Roughly speaking, crossed product is the expected structure for a group ring of a semidirect product group. Therefore crossed products have a ring theory aspect also. This article concentrates on an important case, where they appear in functional analysis.)
Read more about Crossed Product: Motivation, Construction, Properties, Duality, Examples
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—Cecil B. De Mille (1881–1959)
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—Ralph Waldo Emerson (1803–1882)