I was used to write abbreviations like
foo i.e.\ bar but today learned that I could also write them as
foo i.e.\@ bar. Both of these apparently have the effect of keeping the space to its normal inter-word size, as opposed to the larger after-sentence space. The fact that there are two possible ways to express what appears to me the same thing makes me wonder whether I might be missing some part of the picture here.
Is there any reason to prefer one of these over the other? When should I use which?
Unfortunately I haven't found much authoritative documenation about either of these. The latex2e reference manual describes the use of
\@ before the period, but not its use after a period. The Advanced TeXbook doesn't mention
\@ in its index, which might be considered an indication that it's a LaTeX addition. Various questions, answers and comments on this site here mention one, the other or even both, but so far I haven't found a clear rule about when to use which.
So far I'd tend to keep using
\␣ in preference to
\@, because I find it easier to read and because that use is better represented in documentation.