NOTE THAT THESE MAY BE REMOVED.
This is a constructor for a binomial kernel object.
Currently, this object is a named list (with pmf and cdf components).
Here, the PMF is symmetric about zero (in contrast to how a binomial distribution is normally defined), and has zero-probability outside the interval [-hbw, hbw], where:
hbw = (bw - 1) / 2
This object is used inside discrete kernel smoothing.
(In which case, you provide the constructor, not the object).