On the minimum set of physical assumption leading to the

The way of obtaining the Schroedinger equation for a quantum particle in an electromagnetic field is revisited, showing that very few physical assumptions are required. In fact, after having introduced the general formalism of non-relativistic quantum mechanics, it is shown that the structure of the Schroedinger equation for a spinless particle is obtained merely by requiring continuity of space and time, and covariance with respect to Galilean transformation. Both the Correspondence and Uncertainly principles then become 'theorems'