Le 12/09/2013 14:21, Neil Harris a écrit :
On 12/09/13 11:26, Johan Winge wrote: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 WingeDo some mathematicians _really_ use Φ/φ instead of ∅, or does it just look like they're doing so?Careless handwriting of ∅ could indeed look like Φ or even φ, but I doubt they're thinking "phi, the symbol for the empty set" as they do so. [...]
I've heard physicists saying "phi" for the similar ⌀ U+2300 DIAMETER SIGN, in French. So I wouldn't be surprised if some mathematicians would use the same 'mistake' to read out loud formulas containing the empty set.
Fred
