Hicham Mouline wrote:
Hello,
I am trying to spread the ellipsis over many columns of a matrix... lyx
shouts:
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.
Is there a specific miktex (mpm.exe) package I need to see installed?
Rds,
You need AMS math loaded. In LyX, go to Document > Settings... > Math
Options and check "Use AMS math package".
Also, when you enter the command, be sure to start the braces with \{
rather than just {. If you literally type \hdotsfor{3}, say, what
you'll end up with in LaTeX is \hdotsfor\{3\}, escaping the braces, and
then LaTeX will complain about a missing or invalid numerical argument.
If you type \hdotsfor followed by \{, LyX will convert \{ to a matched
pair of braces with an input widget (rectangle) in between them, which
is what you want.
/Paul