How to create an "inverse" \ddots?

p...@garlic.ece.utexas.edu

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Oct 30, 1997, 3:00:00 AM10/30/97

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Hi, folks,

Does anyone know how to create an "inverse"
\ddots? An "inverse" \ddots means
.
.
.

Thanks a lot!

Hung-Ta
p...@vision.ece.utexas.edu

J%org Knappen

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Nov 3, 1997, 3:00:00 AM11/3/97

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In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:

"> " Does anyone know how to create an "inverse"
"> "\ddots? An "inverse" \ddots means
"> " .
"> " .
"> " .
"> "
"> " Thanks a lot!

I suggest doing this symbol in METAFONT. It is easy and staightforward.

--J"org Knappen

"> "Hung-Ta
"> "p...@vision.ece.utexas.edu

Weiqi Gao

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Nov 3, 1997, 3:00:00 AM11/3/97

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J%org Knappen wrote:
>
> In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:
>
> > Does anyone know how to create an "inverse"
> > \ddots? An "inverse" \ddots means
> > .
> > .
> > .
> >
> > Thanks a lot!
>
> I suggest doing this symbol in METAFONT. It is easy and staightforward.

Or get the defition of \ddots, and define your \rddots based on it. You
only need to change two numbers (actually interchange the height of the
first dot with that of the third dot).

--
Weiqi Gao
weiq...@a.crl.com

Daniel Luecking

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Nov 4, 1997, 3:00:00 AM11/4/97

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kna...@iphcip1.Physik.Uni-Mainz.DE (J%org Knappen) writes:

>In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:

>"> " Does anyone know how to create an "inverse"
>"> "\ddots? An "inverse" \ddots means
>"> " .
>"> " .
>"> " .
>"> "
>"> " Thanks a lot!

>I suggest doing this symbol in METAFONT. It is easy and staightforward.

Yes it is, but to make it properly match \ddots, you need to know what
\ddots does. That is, the exact size and shape of the dots, and their
horizontal and vertical spacing. To find this out, look up the
definition of \ddots in plain.tex (or in one of the latex source
files, though I know not which). But while your looking at that, you
should find it very easy to copy the same idea, but reversing the order
of the vertical spacing commands. Voila, no need for Metafont.

--
Dan Luecking Dept. of Mathematical Sciences
luec...@comp.uark.edu University of Arkansas
http://comp.uark.edu/~luecking/ Fayetteville, AR 72101

Stefan Parkvall

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Nov 10, 1997, 3:00:00 AM11/10/97

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luec...@comp.uark.edu (Daniel Luecking) writes:

> kna...@iphcip1.Physik.Uni-Mainz.DE (J%org Knappen) writes:
>
> >In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:
>
> >"> " Does anyone know how to create an "inverse"
> >"> "\ddots? An "inverse" \ddots means
>

> Yes it is, but to make it properly match \ddots, you need to know what
> \ddots does. That is, the exact size and shape of the dots, and their
> horizontal and vertical spacing. To find this out, look up the
> definition of \ddots in plain.tex (or in one of the latex source
> files, though I know not which). But while your looking at that, you
> should find it very easy to copy the same idea, but reversing the order
> of the vertical spacing commands. Voila, no need for Metafont.

I've done that once and put the code in s simple style file which I
enclosed below. I hope that will help

--- iddots.sty

%%
%% Stefan Parkvall, June 24, 1997
%%

\def\iddots{\mathinner{\mkern1mu\raise\p@
\vbox{\kern7\p@\hbox{.}}\mkern2mu
\raise4\p@\hbox{.}\mkern2mu\raise7\p@\hbox{.}\mkern1mu}}

--
Stefan Parkvall, PhD park...@cwc.ucsd.edu
Center for Wireless Communication http://www.s3.kth.se/~parkvall
University of California, San Diego phone: (619) 534-8246
La Jolla, CA 92093 fax: (619) 534-2486

Daniel Luecking

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Nov 11, 1997, 3:00:00 AM11/11/97

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Stefan Parkvall <park...@asteroid.ucsd.edu> writes:

>luec...@comp.uark.edu (Daniel Luecking) writes:

>> >In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:
>>
>>> Does anyone know how to create an "inverse"
>>>\ddots? An "inverse" \ddots means
>>

[snipped my own comments]
>> ...look up the definition of \ddots in plain.tex ... you

>> should find it very easy to copy the same idea, but reversing the order

>> of the vertical spacing commands...

>I've done that once and put the code in s simple style file which I
>enclosed below. I hope that will help

>--- iddots.sty

>\def\iddots{\mathinner{\mkern1mu\raise\p@
> \vbox{\kern7\p@\hbox{.}}\mkern2mu
> \raise4\p@\hbox{.}\mkern2mu\raise7\p@\hbox{.}\mkern1mu}}

To properly match plain's \ddots, the boxes should probably be reversed
also (i.e., the tall \vbox comes last):

\def\iddots{\mathinner{\mkern1mu\raise\p@

\hbox{.}\mkern2mu\raise4\p@\hbox{.}\mkern2mu

\raise7\p@\vbox{\kern7\p@\hbox{.}}\mkern1mu}}

Which brings up the obvious question: Why did Knuth put that \kern7pt
inside the \vbox? If I understand this correctly, the only effect would
be to give \ddots an extra 7pts of height (without any actual ink
there). If that is only meant to influence the spacing in matrices,
that would seem to be better left to fine adjustments in the data, such
as placing struts in the \matrix entries.

Berthold K.P. Horn

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Nov 11, 1997, 3:00:00 AM11/11/97

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luec...@comp.uark.edu (Daniel Luecking) writes:

> >> >In article <63aue8$f5m$1...@geraldo.cc.utexas.edu>, p...@garlic.ece.utexas.edu () writes:

> >>> Does anyone know how to create an "inverse"
> >>>\ddots? An "inverse" \ddots means

> [snipped my own comments]
> >> ...look up the definition of \ddots in plain.tex ... you
> >> should find it very easy to copy the same idea, but reversing the order
> >> of the vertical spacing commands...

Another way is to use math fonts that have both :-)
like Lucida New Math.

--
Berthold K.P. Horn mailto:bk...@ai.mit.edu
Cambridge, Massachusetts, USA
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