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I have a simple expression in my text which refuses to compile and I don't know why:

...\textit{isInterestedIn(Class$\<$? extends ContentChange$\>$ changeClass)}...

The complete error statement goes like this:

! Undefined control sequence.
<recently read> \<
l.298 ...? extends ContentChange$\>$ changeClass)}
mit einem der \textit{Tex...
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

I don't really understand, what's the problem here.

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What do you want. Type only $<$ and $y$. Or do you looking for something like: \langle\text{extends ContentChange}\rangle – Marco Daniel Sep 1 '11 at 11:44
up vote 4 down vote accepted

The command (called control sequence) \< is unknown. \ means the start of a control sequence. Write $<$ or $\backslash<$ instead, the latter if you really need a backslash .

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Thanks man, that did the trick for me. However, I'm a little curious why Texmaker returned me this expression from it's math character table...?! – ubuntudroid Sep 1 '11 at 11:54
One can use \left< and \right> as abbreviations for \left\langle and \right\rangle; even \bigl< and \bigr> are legal. But \< has always been undefined in LaTeX (other than in the tabbing environment). – egreg Sep 1 '11 at 12:56
-1 from me for suggesting $\backslah$ for text mode backslash. For obtaining a backslash in text mode, use \textbackslash; for using < and > in text mode, use T1 font encoding (or an opentype font). – Aditya Sep 1 '11 at 18:13
@Aditya: thanks for explaining the downvote. You could add your comment as answer. Btw. I assume the backslash is not needed at all: See for example public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) here in Java documentation. And for deciding choosing math < or text < I don't see much information of the OP about the context such as encoding or desired shape of <, so I just fixed and explained. – Stefan Kottwitz Sep 1 '11 at 19:21

You do not need to use math mode to get text < and >. A simpler solution is to either use T1 font encoding, or an opentype font (with lualatex or xetex). For example, with pdflatex


or with lualatex

\setmainfont{TeX Gyre Pagella}
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