Product of sub-Gaussian random variables is sub-exponential
= Product of sub-Gaussian random variables is sub-exponential
If $X$ and $Y$ are sub-Gaussian, without requiring independence between them, then $XY$ is <sub-exponential random variable>[sub-exponential]. The inequality $2|XY|\leq X^2+Y^2$ converts exponential-square moment bounds for the factors into an exponential moment bound for the product.