Definition:Projection (*-Algebras)

Definition

Let $\struct {A, \ast}$ be a $\ast$-algebra.

Let $p \in A$ be Hermitian.

We say that $p$ is a projection if and only if

$p^2 = p$

Sources

• 1990: Gerard J. Murphy: C*-Algebras and Operator Theory ... (previous) ... (next): $2.1$: $C^\ast$-Algebras