Definition:Set/Historical Note

Historical Note on Set
The concept of a set first appears in 's posthumous ($1851$) work Paradoxien des Unendlichen (The Paradoxes of the Infinite).

The first investigation into the concept in any depth was made by in his two papers called Beiträge zur Begründung der transfiniten Mengenlehre ($1895$ and $1897$).

It was who defined a set as being:
 * a Many that allows itself to be thought of as a One.
 * --, and , Gesammelte Abhandlungen (Berlin: Springer-Verlag, $1932$)

This definition was directly inspired by a problem raised by in his paper  of $1854$, on the subject of Fourier series.