## \<space>

LaTeX normally leaves a little extra space after sentences. However, it uses a rather simple rule for determining whether a period ends a sentence: it assumes that periods end sentences unless they follow an upper case letter. To let LaTeX know that a period does not end a sentence after, for example, an abbreviation, use \<space>

For example,

Jones, et al.\ (1993) ...

Such a space may also be needed after a text-producing command, such as one defined with \newcommand. As an example, consider

\newcommand{\water}{H\$_2\$O}
\water, \water\ everywhere, but not a drop ...

The first \water command is terminated by the comma; note that LaTeX does not leave a space between the first \water and the comma -- as desired -- and the trailing space is treated as an interword space. However, the second \water command is terminated by the space, but LaTeX would not leave an extra space after this, running "H2Owater" into one word, except for the trailing \ .

An alternate way to indicate the end of a command so that a trailing space is interpreted as an interword space is to use braces:

\water, \water{} everywhere, ...

See \@ for the opposite case