Given a unital C*-algebra a *-closed subspace S containing 1 is called an operator system. One can associate to each subspace of a unital C*-algebra an operator system via .
The appropriate morphisms between operator systems are completely positive maps.
By a theorem of Choi and Effros, operator systems can be characterized as *-vector spaces equipped with an Archimedean matrix order.
Famous quotes containing the word system:
“In the end we beat them with Levi 501 jeans. Seventy-two years of Communist indoctrination and propaganda was drowned out by a three-ounce Sony Walkman. A huge totalitarian system ... has been brought to its knees because nobody wants to wear Bulgarian shoes.... Now they’re lunch, and we’re number one on the planet.”
—P.J. (Patrick Jake)