# \mathbb{stuff} isn't working

1. Oct 25, 2011

### flyingpig

1. The problem statement, all variables and given/known data

On MikTeX, can't enter $\mathbb{R}$

Gives me a statement that says

Code (Text):
! Undefined control sequence.

l.14 $\mathbb {F}$
?
No idea what that means?

2. Oct 26, 2011

### CompuChip

\mathbb is defined in one of the AMS packages, so you probably have to include amssymb or amsfonts or something like that.

3. Oct 26, 2011

### flyingpig

I am a novice in this, how do I introduce that package?

4. Oct 26, 2011

### hotvette

Following should work:

Code (Text):
\documentclass{article}
\usepackage{amsfonts}
\begin{document}
$\mathbb{R}$
\end{document}

#### Attached Files:

• ###### amsfont.jpg
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5. Oct 27, 2011

### flyingpig

That worked, but am I restricted to only one package? Again novice here.

I tried adding \userpackage{amsmath}, but amsmath doesn't exist. I am trying to add an array here.

thanks

6. Oct 27, 2011

### hotvette

I'm not aware of any limitation on how many packages can be used. Whenever I include a reference to a new package MiTek automatically finds and installs it. Btw, I noticed a typo in your last post. It should be \usepackage not \userpackage.

Suggestion: the userguides you can find on the web are quite helpful. Just do a Google search and you'll find a number of them.

There is also a Google Latex user group that can be quite helpful:

Last edited: Oct 27, 2011
7. Oct 27, 2011

### flyingpig

Yes you are right, I added an "r". I also have looked online, but I thought there was something wrong with it because it didn't work initially and it was the "r" and I thought the package doesn't even exist.

Thanks