Section 6.2: Complex
Gaussian kernel (6.23)
[[latex($k(\mathbf{x},\mathbf{xp}) = exp(-||\mathbf{x} - \mathbf{xp}||2 / 2\sigma2) $)]] (6.23)
is this valid? (6.24)
[[latex($ ||\mathbf{x} - \mathbf{xp}||2 = \mathbf{x}T\mathbf{x} + (\mathbf{xp})T\mathbf{xp} - 2\mathbf{x}T\mathbf{xp} $)]]
substitute into 6.23 to give 6.25
use 6.14 and 6.16, ie latex($ f(\mathbf{x})k_{1}(\mathbf{x},\mathbf{x^p})f(\mathbf{x^p}) $) and latex($ exp(k_{1}(\mathbf{x},\mathbf{x^p})) $)
to see that it is valid.
We can also replace latex($\mathbf{x}^T,\mathbf{x^p} $) in the above with a nonlinear Kernel latex($\kappa(\mathbf{x},\mathbf{x^p}) $)
