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, especially in Bayesian analysis, the fundamental part of a probability density function (pdf) or probability mass function (pmf) is the simplified form where all non-variable-related components are eliminated. These omitted factors often relate to the parameters of the pdf or pmf and serve as part of the normalization constant.