Given two vectors $v, u \in \mathbb{R}^n$ (i.e. column vectors), then the dot product of them is defined like this
$$\sum_{i=1}^n v_i * u_i$$
Or usually it can be expressed in matrix-product notation as follows $$v^Tu$$
I've now encountered a place where instead of $T$, $H$ is used, that is
$$v^Hu$$
I noticed that $H$ is also used in my slides in the formula of the outer product, so this is not intrinsic to the inner product.
Why is $H$ being used? Does it have a particular meaning?
$H$ stands for "Hermitian tranposition", which is the same operation as transposition for real matrices. But when dealing with complex ones, you have to conjugate each coefficient as well.
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