From: Computational purification of individual tumor gene expression profiles leads to significant improvements in prognostic prediction
Probability density/mass functiona, b
Dirchlet x | a = Γ ∑ k = 1 K a k ∏ k = 1 K Γ a k ∏ k = 1 K x k a k - 1
Multinomial y | π = ∑ k = 1 K y k ! ∏ k = 1 K y k ! ∏ k = 1 K π k y k