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.)
Other articles related to "products, product, crossed product":
... The construction of semidirect products can be pushed much further ... The Zappa–Szep product of groups is a generalization which, in its internal version, does not assume that either subgroup is normal ... There is also a construction in ring theory, the crossed product of rings ...
... algebra A to be the complex numbers C, then the crossed product is called the von Neumann group algebra of G ...
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