The ASCII character number 237, sometimes called a “slashed zero”, is with other mathematical symbols that are used in describing sets. Is it the symbol for a “null set”?
The symbol for a “null set”, I read recently, is a Scandinavian letter, not English, not a zero. What’s the letter called? What other uses does this symbol have?
BTW I just get an underscore when I type ALT237, so I assume the font SDMB is displaying with on my screen just doesn’t support this symbol. Anybody know different?
And, yes, I know ASCII is 7 bit and doesn’t really go above 127 - I’m being more convenient than rigorous - I think I am referring to the “IBM set”, or the “Terminal Font” in Windows. Sorry to offend…
Interesting. The capital O with a slash is Unicode 216. The symbol for the empty set is Unicode 8709. They are implemented in HTML as Ø and ∅, respectively. If your browser shows them, here they are:
Ø ∅
They’re not the same glyph in this font, and the HTML specs usually tell you if you can use the same glyph for two different characters (as they do with capital Sigma and the summation sign). Unfortunately, I can’t find the names of the symbols. So far the best I’ve been able to find is “capital O slash” and “empty set”.
The null set or empty set in mathematics is represented by a symbol that looks like a slashed zero. Some sources say that it comes from the letter used in Danish and Norwegian, while others describe it as being the Greek letter “phi.” In any case, mathematicians just call it “empty set.”
Ø is the last letter in the Norwegian and Danish alphabet, we Swedes has the Ö instead.
In charset iso-8859-1
alt + 0216 = Ø