Exercise 12.14: Kernel and Function Boundedness
\begin{align} |f(x)| = |\langle f, k(\cdot, x) \rangle| \leq \| f \| \sqrt{k(x, x)} \leq b \end{align}
\begin{align} |f(x)| = |\langle f, k(\cdot, x) \rangle| \leq \| f \| \sqrt{k(x, x)} \leq b \end{align}