Consider the Gaussian kernel function K(i,j) defined by
$$ K(i,j)= e^{-\alpha*\left \| x_i-x_j \right \|} $$ where $x_i$ is a point in a $R^d$ space.
Show K is Lipschitz continuous. I know the definition for Lipschitz continuous, but I don't know how to use it here. Has someone a hint?