A note on Sum, Difference, Product and Ratio of Kumaraswamy Random Variables

Explicit expressions for the densities of S = X 1 + X 2 , D = X 1 − X 2 , P = X 1 X 2 and R = X 1 / X 2 are derived when X 1 and X 2 are independent or sub-independent Kumaraswamy random variables. The expressions appear to involve the incomplete gamma functions. Some possible real life scenarios are mentioned in which such quantities might be of interest.