Another LaTeX problem: \box necessity operator

[Gwern Branwen]

Wikipedia's summary of the modal necessity operator:

'U+25FB ◻ or U+25A1 □: modal operator for "it is necessary that" (in
modal logic), or "it is provable that" (in provability logic), or "it
is obligatory that" (in deontic logic), or "it is believed that" (in
doxastic logic).'

The possibility operator is \diamond, and necessity is \box. \diamond
works fine, but \box doesn't appear at all. I deleted all the PNGs in
.mnemosyne/latex to make sure, but that didn't fix the problem. Nor
can I see any apparently related errors in the intermediate files,
attached.

--
gwern

[Peter Bienstman]

Hi Gwern,

After some googling, I came across this file
http://www.ctan.org/tex-archive/info/symbols/comprehensive/symbols-a4.pdf
which seems to say its \Box instead of \box, and requires e.g. the
amsfonts package

Edit your .mnemosyne/latex/preamble to look e.g. something like this:

\documentclass[12pt]{article}
\usepackage{amsfonts}
\pagestyle{empty}
\begin{document}

Cheers,

Peter

>  latex_out.txt
> < 1KViewDownload
>
>  xwd-128232272727058.png
> 28KViewDownload
>
>  xwd-128232273827073.png
> 29KViewDownload
>
>  tmp.log
> 3KViewDownload
>
>  tmp.tex
> < 1KViewDownload

[Gwern Branwen]

On Fri, Aug 20, 2010 at 2:55 PM, Peter Bienstman
<Peter.B...@ugent.be> wrote:
> Hi Gwern,
>
> After some googling, I came across this file
> http://www.ctan.org/tex-archive/info/symbols/comprehensive/symbols-a4.pdf
> which seems to say its \Box instead of \box, and requires e.g. the
> amsfonts package
>
> Edit your .mnemosyne/latex/preamble to look e.g. something like this:
>
> \documentclass[12pt]{article}
> \usepackage{amsfonts}
> \pagestyle{empty}
> \begin{document}
>
> Cheers,
>
> Peter

Turns out amsfonts is installed as part of texlive-base. Which makes
me angrier about the lack of error messages - would it kill LaTeX to
have emitted an error message like 'you tried to use \Box, which is
not imported but is available in the amsfonts package!' (I did try the
uppercase version a few times; strangely, both \diamond and \Diamond
work, but \box doesn't...)

Adding the \usepackage fixed it, thanks.

--
gwern

[Peter Bienstman]

> Turns out amsfonts is installed as part of texlive-base. Which makes
> me angrier about the lack of error messages - would it kill LaTeX to
> have emitted an error message like 'you tried to use \Box, which is
> not imported but is available in the amsfonts package!'

Strangely enough, my latex setup did give such an error when I use try to use
\Box:

This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian)
restricted \write18 enabled.
entering extended mode
(./tmp.tex
LaTeX2e <2009/09/24>
Babel <v3.8l> and hyphenation patterns for english, usenglishmax, dumylang,
noh
yphenation, loaded.
(/usr/share/texmf-texlive/tex/latex/base/article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(/usr/share/texmf-texlive/tex/latex/base/size12.clo)) (./tmp.aux)

! LaTeX Error: Command \Box not provided in base LaTeX2e.

See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...

l.4 $\Box
$
[1] (./tmp.aux) )
(see the transcript file for additional information)
Output written on tmp.dvi (1 page, 152 bytes).
Transcript written on tmp.log.

[Gwern Branwen]

What can I say? I provided the tmps, and I don't recall any such error
in them. Perhaps Ubuntu changed something importing from Debian, or
perhaps texlive is a different set of packages from Debian's TeX
packages.

--
gwern