Operator Algebras

Continuous functional calculus

In mathematics, particularly in operator theory and C*-algebra theory, the continuous functional calculus is a functional calculus which allows the application of a…

Positive element

In mathematics, an element of a *-algebra is called positive if it is the sum of elements of the form a^*a.

Unitary element

In mathematics, an element of a *-algebra is called unitary if it is invertible and its inverse element is the same as its adjoint element.

Self-adjoint

In mathematics, an element of a *-algebra is called self-adjoint if it is the same as its adjoint element.