Lowercase
pi
pi - 3.14159.. constant
Pi
Pi - (product)
alpha
Alpha - (scikit-learn regularization parameter)
sigma
sigma - (standard deviation)
Sigma
Sigma - (sum)
gamma
Gamma - (distribution)
beta
Beta (distribution & parameter weights)
Delta
Delta - (change)
kappa
Kappa - Cohen's kappa
mu
Mu - (population mean)
chi
Chi - (distribution & Chi2 test)
lambda
Lambda (Poisson distribution, regularization parameter)
omega
Omega - (best case in Big-O time complexity)