I'm new to TeX and tried to enter an equation using \mathbb. I received a prompt
LaTeX Error: \mathbb allowed only in math mode.
See the LaTeX manual or LaTeX Companion for explanation.
I thought I would try here for an explanation.
3 Answers
You enter math mode by typing a dollar sign $, and you leave math mode by typing another dollar sign $. You should take a look at Chapter 3 of The Not So Short Introduction to LaTeX
answered Apr 12, 2011 at 20:27
I guess that an even better way to enter math mode is to use \( and \), as discussed in this answer.
TeX knows several modes, two of them are math mode and display math mode. Typesetting of ordinary text such as words nor numbers is different compared to mathematical formulas or a mathematical identifier such as x, which should look different from the text x (it does differ here in this editor only vaguely)
In order to let TeX know which mode should be used, there are indicators to enter math mode:
- Inline math mode, being entered
$and closed with$ - Display math mode, used with an enclosing
$$...$$in plainTeXor with\[...\]inLaTeX - Typing inside
\begin{math}...\end{math}inLaTeX - Several math environments in
LaTeXenter the math mode automatically, such asequation,align,alignedat,gatheretc.
Several characters/symbols being connected to math content require entering the math mode, such as \mathbb{R} etc.
\mathbbtypesets capital letters as "black-board bold" symbols, such as the symbol ℝ which usually denotes the set of real numbers (and which is produced by\mathbb{R}in math mode).