The fuzzy P-value enrichment score can be calculated by decomposing the null distribution into two parts; firstly we denote by Z the number of non-zero grades of membership in the fuzzy intersection between two null fuzzy sets: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\{ S,\ {m_{a,\ null}}\} \cap \{ S,\ {m_{b,\ null}}\}$\end{document}. Then Z is a random variable that is distributed by the hypergeometric distribution: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}\begin{equation*}P(Z = z) = \frac{{\left( {\begin{array}{*{20}{c}} {{N_a}}\\ z \end{array}} \right)\left( {\begin{array}{*{20}{c}} {|S| - {N_a}}\\ {{N_b} - z} \end{array}} \right)}}{{\left( {\begin{array}{*{20}{c}} {|S|}\\ {{N_b}} \end{array}} \right)}}\end{equation*}\end{document}
