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From: dhosek@sif.claremont.edu (Hosek, Donald A.)
Newsgroups: comp.text.tex
Subject: Re: \@ in TeX ?
Message-ID: <8090@jarthur.Claremont.EDU>
Date: 12 Aug 90 16:47:53 GMT
References: <1990Aug11.062334.27535@nmt.edu>
Sender: news@jarthur.Claremont.EDU
Reply-To: dhosek@sif.claremont.edu
Organization: Harvey Mudd College
Lines: 40

In article <2090@wn1.sci.kun.nl>, eykhout@wn2.sci.kun.nl (Victor Eijkhout) writes...
->nraoaoc@nmt.edu (Daniel Briggs) writes:

->>LaTeX provides a simple control sequence to tell the
->>program that a given period after a capital letter actually ends a sentence,
->>and is not an abbreviation.  Lamport's example of this is

->> The Romans wrote I + I = II\@.  Really!

->>I looked up the definition of \@ in LaTeX, and it turns out to be some
->>fairly obscure arcana.  It sets some interword penalty or other to 1000.
->Nope. It sets the spacefactor, which is thousand times the
->ratio by which the stretch of spaces should be magnified.

->The trick is this (and it's in the TeX book!): the '.' will set the
->spacefactor to 3000 (so spaces after . will stretch thrice as hard), 
->but if the current space factor is <1000, TeX will
->only set it to 1000. Now by inserting \@, you set the space factor
->manually to 1000, so the subsequent period will increase the 
->spacefactor to 3000. The reason this is necessary, is that all
->capital letters have spacefactor 999, which is done precisely to
->prevent double spacing after initials.

->Now for the simple remedy: the space factor is also set to 1000
->after boxes and rules, so you might write
->        The romans wrote I + I = II\hbox{}. Really!

Or even simpler, "The romans wrote I + I = II\null."

cf. _The TeXbook_, p. 311.

-dh


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