How can I make comments inside an long equation, something like:
\begin{equation}
G(r)
% comment here
= \frac{A}{B}
= \frac{\frac{t_c}{3}}{2 \cdot \frac{2t_b + t_v + t_c}{r}} = \frac{t_c}{6 \cdot (2t_b + t_v + t_c)} \cdot r
\end{equation}
[Tex/LaTex] How to make comments inside an equation
amsmathequations
Related Solutions
First: think carefully whether that is the right thing to do, then don't do it. Most symbols for footnote marks can have a mathematical meaning. I once spent several minutes wondering about the meaning of a mathematical expression before I deduced that one of the exponents had to be a footnote mark. My preferred methods of explaining parts of an equation are to explain it in words either before or after the equation, or within the equation as a comment:
\documentclass{article}
\begin{document}
In the following expression, $q$ is required to be an integer:
\[
n = q\cdot k
\]
And here is another equation:
\[
a^2 + b^2 = c^2 \qquad\text{($c$ is required to be an integer.)}
\]
\end{document}
If one really must have a footnote, you can just try the \footnote command. This can fail in some circumstances, in which case one can use the pair of commands \footnotemark and \footnotetext, the latter outside the math environment:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
Plain footnote works:
\[
X^2 = Y\footnote{$Y$ is a matrix}
\]
Need to separate mark and text:
\begin{align}
X^2 &= Y\footnotemark\\
Y^2 &= Z
\end{align}\footnotetext{$Y$ is a matrix}
\end{document}
Unfortunately, it can happen that the \footnotetext{...} ends up on the next page.
I don't know a simple means to prevents that, except to move it before the math environment when it happens.
A solution with small bullets, and your code simplified, using the nccmath , relsize and braket packages. I patched the definition of the \Set command thanks to David Carlisle to improve the spacing of the braces.
Note that "discr" is actually a math operator, and I declare it as such, in order to have better horizontal spacings.
\documentclass[11pt, a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[textwidth = 15cm]{geometry}
\usepackage{lmodern, amssymb}
\usepackage{mathtools}
\usepackage{braket, relsize, nccmath}
\renewcommand\Set[1]{%
\csname Set \endcsname{\mskip-\medmuskip#1\mskip-\medmuskip}}%
\DeclareMathOperator{\disc}{disc}
\pagestyle{empty}
\begin{document}
\begin{equation}
V_{p}=\Set{%
F\in\Phi | %
\begin{medsize}\begin{array}{@{\mathsmaller{\bullet}\enspace}l@{}}
p^2 \nmid \disc(F) \quad \text{if}\enspace p \neq 2\\[1ex]
\disc(F)\equiv 1\pmod 4 \vee \disc(F)\equiv 8\vee 12
\pmod{16} \quad\text{if} \enspace p =2
\end{array}\end{medsize}
}%
\end{equation}
\end{document}
Best Answer
Do you mean something like this? If you are referring to setting source code (LaTeX listings) you should clarify that a bit in your question.