In statistics, especially in Bayesian statistics, the kernel of a probability density function (pdf) or probability mass function (pmf) is the form of the pdf or pmf in which any factors that are not functions of any of the variables in the domain are omitted. Note that such factors may well be functions of the parameters of the pdf or pmf. These factors form part of the normalization factor of the probability distribution, and are unnecessary in many situations.
In statistics, particularly in Bayesian statistics, the core of a probability density function (pdf) or probability mass function (pmf) is the form of the pdf or pmf where all factors unrelated to variables in the domain are removed. These factors may be related to the parameters of the pdf or pmf and contribute to the normalization factor.