Definition:Adjoint (Norm Theory)

Definition

Let $X$ and $Y$ be normed vector spaces.

Let $A: X \to Y$ be a linear operator between $X$ and $Y$.

Let $A^*: Y^* \to X^*$ be the linear operator defined as:

$\forall x, y \in Y: \innerprod {A x} y = \innerprod x {A^* y}$

Then $A^*$ is the adjoint of $A$.

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Also known as

$A^*$ is also known as the dual of $A$.

Sources

• 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): adjoint: 1. b.