As quantum mechanics developed further, it turned out that there were a large number of things which were not directly encompassed in the Schrödinger equation—such as the spin of the electron, and various relativistic phenomena.

The mathematics that is involved is particularly simple, involving simple algebraic operations and no differential equations or at most only very simple ones.

As quantum mechanics developed further, it turned out that there were a large number of things which were not directly encompassed in the Schrödinger equation—such as the spin of the electron, and various relativistic phenomena.

The mathematics that is involved is particularly simple, involving simple algebraic operations and no differential equations or at most only very simple ones.

As quantum mechanics developed further, it turned out that there were a large number of things which were not directly encompassed in the Schrödinger equation—such as the spin of the electron, and various relativistic phenomena.

The mathematics that is involved is particularly simple, involving simple algebraic operations and no differential equations or at most only very simple ones.

As quantum mechanics developed further, it turned out that there were a large number of things which were not directly encompassed in the Schrödinger equation—such as the spin of the electron, and various relativistic phenomena.

The mathematics that is involved is particularly simple, involving simple algebraic operations and no differential equations or at most only very simple ones.