General ⇒ finding/importing symbols

[junket]

Hello there, I am new to latex and would greatly appreciate some basic advice, whether directly, or by way of some useful links, or even both.
I have just downloaded teXnicCenter and the first thing I have noticed is that it does not seem to be immediately possible to double overline a symbol. I need double overlining for Cantor, who uses double overlining for the cardinal, and single overlining for the ordinal, so I need to be able to do both.
I am also looking for Cantor's equivalence symbol - which looks like a bit like an S on it's side - it is not among the operators there.
It is quite important for the nature of my work that I can cite extracts from Cantor (and others) exactly, because there is some discussion of notation involved.
I am also going to need to use some Begriffsschrift later on. I understand this is possible with latex, but if anyone has had any experience with this that they might consider beneficial to me I would be grateful for their insights.
I suppose my basic question is: how does one go about importing symbols that do not seem to be available (or maybe they are available, I can't find the double overline)? Is there a very useful place to look for such symbols?

I am sorry if this question is basic or even repetitive, I am very new to latex and a little confused with the whole layout.
Any link to a very helpful tutorial for teXnicCenter would also be very useful.
Thank you so much in advance, and my apologies if my questions are tedious.
Junket

[frabjous]

the first thing I have noticed is that it does not seem to be immediately possible to double overline a symbol.

You can use the \overline command twice, e.g., \overline{\overline{A}} will produce a twice-overlined A.

I am also looking for Cantor's equivalence symbol - which looks like a bit like an S on it's side - it is not among the operators there.

Where? I think you want \sim -- If that's not it, could you post a link to an image of it? You could also try detexify for hand-drawn symbol recognition.

I am also going to need to use some Begriffsschrift later on. I understand this is possible with latex, but if anyone has had any experience with this that they might consider beneficial to me I would be grateful for their insights.

Do you mean Frege's Begriffsschrift? The begriff package is wonderful for this. You may also need the fge package for some of the rarer symbols from Frege's work.

I have a fair bit of experience with it. This page on the Arché Wiki might get you started.

I suppose my basic question is: how does one go about importing symbols that do not seem to be available (or maybe they are available, I can't find the double overline)? Is there a very useful place to look for such symbols?

The LaTeX Comprehensive Symbol Guide, in addition to giving a pretty comprehensive list of what's available, gives advice for creating your own when need be. Personally, even though I do some work on the history of logic, I've been able to find almost everything I need. But do feel free to ask here if you would like some additional advice.

[junket]

Thank you frabjous,
1) I did not think you could do the overline twice, thanks!
2) Yep, it is indeed /sim!
3) I only need the basic candlestick stuff at the moment, no ancestrals even, so this package should work fine!
You've been really helpful. Thank you so much for both the direct advice and the links!
It looks like laTex is exactly what I need.

[junket]

Hello again,

Further to my previous questions I have one niggling issue remaining.
When I want to double overline e.g. M, I am doing this
$\overline{\overline{M}}$
It works re: the double overhead but it is putting M in italics.
The same happens for the single overline
$\overline{M}$
Any ideas on how to get the M out of italics would be welcome.
Thanks!

Junket

[junket]

P.S. I have already checked "The Comprehensive Latex Symbols List" but cannot locate what I am looking for (perhaps it is there however and I have searched badly).
But basically, I have tried quite hard to find this symbol, so I would be very grateful if someone was able to help.
Thanks

[frabjous]

It normally puts text in math mode in italics.

The \mathrm command can be used to get Roman (upright) text in mathmode.

So try:

\overline{\overline{\mathrm{M}}}

If you're going to use this a lot, I would define my own command:

\newcommand{\ddM}{\ensuremath{\overline{\overline{\mathrm{M}}}}}

Then you can just use \ddM for a double-overlined Roman M.

[junket]

Thanks again frabjous,

That's brilliant.

I adapted your newcommand like this:

\newcommand{\ddM}[1]{\ensuremath{\overline{\overline{\mathrm{#1}}}}}

so that I can pass it a text variable.

Thanks!

[localghost]

Now that the problem is solved, please mark the topic accordingly as written in Section 3 of the Board Rules (to be read before posting).


Best regards and welcome to the board
Thorsten