I'm not mathematician... I have a question:
If I have a variable $n$ that can evolve in time. This variable have a probability distribution $D$.
Is there a mathematical "tool" that permit to obtain the expression a differential equation such as for any type of distribution $D$:
$\frac{dn}{dt} = f(D,n)$
EDIT : If I do something like : $\frac{dn}{dt} = \tau (D-n)$ does it mean that $n$ will follow $D$ at the velocity $\tau$ ?