General Purpose PostScript Generating Utility
7.3.3.3 Differences with LaTeX
The following symbols, inherited from the style sheet Symbol
, are
not supported by LaTeX:
`\Alpha', `\apple', `\Beta', `\carriagereturn',
`\Chi', `\Epsilon', `\Eta', `\florin', `\Iota',
`\Kappa', `\Mu', `\Nu', `\Omicron', `\omicron',
`\radicalex', `\register', `\Rho', `\suchthat',
`\Tau', `\therefore', `\trademark', `\varUpsilon',
`\Zeta'.
LaTeX is more demanding about special symbols. Most of them must be
in socalled math mode, which means that the command must be inside
`$' signs. For instance, though
 If \forall x \in E, x \in F then E \subseteq F.

is perfectly legal in PreTeX, it should be written
 If $\forall x \in E, x \in F$ then $E \subseteq F$.

for LaTeX. Since in PreTeX every `$' is discarded (unless
quoted by a `\'), the second form is also admitted.