To typeset that H is a normal subgroup of G, I would use H\unlhd G.
However, the result doesn't satisfy myself, since the G seems too close to the
triangle:
Adding a space \ makes "too much space".
Is there a neat way to typeset such a thing ?
[Tex/LaTex] Normal subgroups
amsmathmath-modespacing
Related Solutions
TeX has a finely balanced system of setting spaces between various types of math "atoms". For example, consider the following simple formula:
$y = b + cx$
Observe that the distance between y and = (and also between = and b) is slightly larger than that between b and +, which again exceeds that between c and x. This is done on purpose, of course, and the choices involved have proven their desirability over decades.
If you were to systematically increase the spacing between any two "atoms" that are multiplied together (such as c and x in the example above), you should also be willing to increase the spacing between all other types of "atoms" in order to preserve the overall balance. To claim that this would be a rather tricky enterprise would be a rather strong understatement.
In short, it's best not only to get used to TeX's way of typesetting mathematics but also to appreciate it for the high standard it sets. TeX's method is the standard against which all other systems for typesetting mathematics are judged and against which they, regrettably, almost invariably fail.
cases sets \arraystretch to 1.2. You can decrease this value:
\documentclass{article}
\usepackage{amsmath}
\makeatletter
\def\env@cases{%
\let\@ifnextchar\new@ifnextchar
\left\lbrace
\def\arraystretch{1}%
\array{@{}l@{\quad}l@{}}}
\makeatother
\begin{document}
\begin{equation}
f(x) = \begin{cases}
g_1(x), & \text{if condition 1}; \\
g_2(x), & \text{if condition 2}; \\
g_3(x), & \text{if condition 3}; \\
g_4(x), & \text{if condition 4}; \\
g_5(x), & \text{if condition 5}; \\
g_6(x), & \text{if condition 6}; \\
g_7(x), & \text{if condition 7}. \\
\end{cases}
\end{equation}
\end{document}
Best Answer
The same symbol is also available as
\trianglelefteqfrom theamssymbpackage. It gives a much wider spacing.