Setting the symbol for "interior"
Ulrich
in Bourbaki, i.e. with a \circ above the set (e.g. A). It is unclear
for me how to do this correctly:
** if I use \stackrel ( $ \stackrel{ \circ }{ A } $, then the \circ
is not centered.
** If I use $\widering{A \cap \complement{B}}$ , then the \widering
looks not fine (using the mathabx-package).
Any suggestions how to do this correctly?
Thanks
Ulrich
Philipp Stephani
Lars Madsen
In our books they've mostly used something like A^\circ, which does not
suffor from the same problems as you describe above.
For example how do you specify the interior of A \cup B ?
--
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Ulrich
Not working ( I have loaded amsmath-package)
Ulrich
Philipp Stephani
This example works with or without amsmath (only the first is correct,
of course):
\documentclass{minimal}
\begin{document}
$\mathring A \; \mathring{A{}} \; \stackrel{\circ}{A}$
\end{document}
Ulrich
OK, then I have to dig where the problem is. The example is working.
Maybe because I am using lucida ? Let me check.
Thanks
Ulrich
G. A. Edgar
<dal...@RTFMSIGNATUREimf.au.dk> wrote:
> Ulrich wrote:
> > I would like to set the (topological) interior of a set like the one
> > in Bourbaki, i.e. with a \circ above the set (e.g. A). It is unclear
> > for me how to do this correctly:
> >
> > ** if I use \stackrel ( $ \stackrel{ \circ }{ A } $, then the \circ
> > is not centered.
> > ** If I use $\widering{A \cap \complement{B}}$ , then the \widering
> > looks not fine (using the mathabx-package).
> >
> > Any suggestions how to do this correctly?
> >
> > Thanks
> > Ulrich
>
> In our books they've mostly used something like A^\circ, which does not
> suffor from the same problems as you describe above.
>
> For example how do you specify the interior of A \cup B ?
You illustrate the difficulty. Classically you would have A \cup B,
and a curve over it (sort of an arc of a circle, curving down at the
ends), then the \circ above that. We can understand why typesetters
charged extra to do mathematical text.
Now: if interior is A^\circ, shouldn't the closure also be shown at the
upper right and not directly above the letter?
A side note. In some old texts you see an inverse image not shown as
f^{-1}(a), but instead the -1 is moved to the left a bit so the minus
sign as directly above the f. Another reason typesetters hated it.
--
G. A. Edgar http://www.math.ohio-state.edu/~edgar/
Lars Madsen
> In article <hkuch5$mpr$1...@news.net.uni-c.dk>, Lars Madsen
> <dal...@RTFMSIGNATUREimf.au.dk> wrote:
>
>> Ulrich wrote:
>>> I would like to set the (topological) interior of a set like the one
>>> in Bourbaki, i.e. with a \circ above the set (e.g. A). It is unclear
>>> for me how to do this correctly:
>>>
>>> ** if I use \stackrel ( $ \stackrel{ \circ }{ A } $, then the \circ
>>> is not centered.
>>> ** If I use $\widering{A \cap \complement{B}}$ , then the \widering
>>> looks not fine (using the mathabx-package).
>>>
>>> Any suggestions how to do this correctly?
>>>
>>> Thanks
>>> Ulrich
>> In our books they've mostly used something like A^\circ, which does not
>> suffor from the same problems as you describe above.
>>
>> For example how do you specify the interior of A \cup B ?
>
> You illustrate the difficulty. Classically you would have A \cup B,
> and a curve over it (sort of an arc of a circle, curving down at the
> ends), then the \circ above that. We can understand why typesetters
> charged extra to do mathematical text.
>
> Now: if interior is A^\circ, shouldn't the closure also be shown at the
> upper right and not directly above the letter?
>
this is why mathematicians has to think a little more about their
syntax. It might work well on paper, but in type it is not always good.
Similar when people ask why \widehat only stretches to a certain width.
> A side note. In some old texts you see an inverse image not shown as
> f^{-1}(a), but instead the -1 is moved to the left a bit so the minus
> sign as directly above the f. Another reason typesetters hated it.
>
I've seen book using something similar to {}^tA to mark the transpose of
the matrix A, while other books placed it after the A.
Makes A^tA very interresting to read in a thesis, if they haven't
specified which syntax they are using.
Ulrich
>
> \documentclass{minimal}
> \begin{document}
> $\mathring A \; \mathring{A{}} \; \stackrel{\circ}{A}$
> \end{document}
>
> --
\usepackage[altbullet]{lucidabr}
caused the trouble. I comment it out and everything is working now.
Thanks for the hint.
@ G.A.Edgar, you are right. But this is fine tuning. But it is just
for the students and not for publishing.
William F Hammond
> I've seen book using something similar to {}^tA to mark the transpose
> of the matrix A, while other books placed it after the A.
(I first noticed this notation in Chevalley's book on Lie Groups, and
I still use it. It reduces clutter when, for example, both tranposes and
inverses are at play.)
As for setting it with LaTeX, the following is more semantically helpful
if not much better visually:
\usepackage{mathtools} % loads a number of other things including amsmath
...
$\prescript{t}{}{A}$
-- Bill
jfh
wrote:
> In article <hkuch5$mp...@news.net.uni-c.dk>, Lars Madsen
I was charmed to find another notation for an inverse function in G N
Watson's "A treatise on the theory of Bessel functions" (2nd ed. 1944,
Cambridge University Press) p.280 where the function
inverse to \psi is \psi rotated 180 degrees in Sonine's theorem.
(Watson explained that that symbol was Sonine's own, in 1870. Nobody
else I know of has used it, perhaps because there are too many letters
that either look the same when rotated 180 deg, or that turn into
other letters one might wish to use.)
John Harper