Definition:Internal Orthogonal Sum (Bilinear Space)

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Definition

Let $\mathbb K$ be a field.

Let $\left({V, f}\right)$ be a reflexive bilinear space over $\mathbb K$.

Let $U, W \subset V$ be subspaces of $V$.


Then $V$ is the internal orthogonal (direct) sum of $U$ and $W$ if and only if:

$V = U \oplus W$, that is, $V$ is the internal direct sum of $U$ and $W$
$U \perp W$, that is, $U$ and $W$ are orthogonal.


This is denoted: $V = U\oplus W$.


Also denoted as

The internal orthogonal sum is also denoted with a $\perp$ inside a $\bigcirc$, but this symbol is not included as standard in $\LaTeX$.


Also see


Sources