Operator Algebrae/Printable version


Operator Algebrae

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Von Neumann algebrae

The operator algebra

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Definition (operator algebra):

Let   be a Banach space over the field   or  . Consider the set   of bounded and linear functions from   to itself. This

Operator topologies

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Topologies on a Banach space

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Definition (weak topology):

Let   be a Banach space, and let   be its dual space. The weak topology on   is defined to be the initial topology with respect to the maps  , where   ranges over  .

Theorem (properties of the weak topology):

Topologies exclusively for operator spaces

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Proposition (bounded operators on a normed space form a Banach space under norm topology):

Let   be a Banach space, and equip the space   with

Definition (uniform topology):

Von Neumann algebrae, basic constructions

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Definition (von Neumann algebra):

A von Neumann algebra is a subalgebra   which is closed under the weak operator topology.

Von Neumann bicommutant theorem

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