I have two different 2D Homogeneous Poisson Point Processes $Λ_1$ and $Λ_2$ with densities $λ_1$ and $λ_2$. The PDF of the distance of the nearest point to the origin $(0,0)$ for each HPPP is known
$f_{R_1}(r)=2πλ_1re^{(-λ_1πr^2)}$, $f_{R_2}(r)=2πλ_2re^{(-λ_2πr^2)}$
If $R_1$ is the random variable of the distance between the origin and the nearest point to the origin of $Λ_1$ and $R_2$ is the random variable of the distance between the origin and the nearest point to the origin of $Λ_2$, I am interested in finding the PDF of the distance between these two points (that belong to different HPPPs).