What mathematical structures are known as von Neumann algebras?

Von Neumann algebras are mathematical structures defined as special algebras of all bounded linear operators acting on a Hilbert space.1

Originally introduced by John von Neumann between 1929 and the 1940s, these structures were developed to provide mathematical techniques suited to the study of quantum phenomena. Initially referred to as "rings of operators," they became a significant area of study in the 1930s when mathematicians began classifying their factors. The field saw a resurgence of interest in the late 1960s, leading to further developments in operator theory and applications in areas such as differential geometry and ergodic theory.21