On Wed, 11 Sep 2013 20:29:51 +0200, Hans Aberg <[email protected]> wrote:
... The symbol for the empty set ∅ is originally a Greek letter phi ϕ, ans some use the latter.
According to the autobiography of André Weil, quoted at http://jeff560.tripod.com/set.html, the empty set symbol ∅ was inspired by the Scandinavian Ø, and would then have nothing to do with the Greek phi, except for a superficial resemblance. I'm aware that some mathematician indeed do use Φ/φ, supposedly due to this misconception and/or lacking coverage in fonts and/or carelessness, but I find it terribly annoying. Really, it is no more correct than using ß in lieu of β.
-- Johan Winge
