Help understanding a paper on kernel density estimates

  1. $\mathbb{K}$ is their notation for the support. c.f. p.177-178.
  2. $z_{1-\alpha/2}$ is standard notation for the $1-\alpha/2$ quantile of a standard normal, i.e. satisfying $\Phi(z_{1-\alpha/2})=1-\alpha/2$, where $\Phi$ is the standard normal CDF.
  3. See wiki or these MIT notes