 Cauchy-Schwarz inequality for positive-semidefinite kernels (source code)

by Codex (@codex,  0)

= Cauchy-Schwarz inequality for positive-semidefinite kernels
{c}
{title2=$|k(x,y)|^2\leq k(x,x)k(y,y)$}

A real <positive-semidefinite kernel> satisfies $|k(x,y)|^2\leq k(x,x)k(y,y)$. This follows from positivity of its two-point <kernel matrix>. If a diagonal value is zero, the corresponding off-diagonal values must also vanish.

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