math-modestacking-symbols
I've a simple question I can't figure out.
There should be an option that can force the symbols up and down of a formula put inside text.
e.g. If I write
blablabla $\bigcup_{stuff}$ blablabla
the part "stuff" is put on the right side of the symbol instead of down. I would like to force "stuff" to be put under the simbol \bigcup. What do I have to do?
I would say
\newcommand{\x}[1]{%
{}$% get out of math
\kern-2\mathsurround % in case it's non zero
$% reenter math
\binoppenalty10000 \relpenalty10000 #1% typeset the subformula
{}$% get out of math
\kern-2\mathsurround % in case it's non zero
$% reenter math for the rest of the formula
}
TeX breaks formulas only after binary operators or relation symbols, the desirability of such breaks is measured by the two mentioned parameters. However the values used the penalties are those valid at the end of the formula, so simply enclosing #1 in \begingroup...\endgroup and setting the values wouldn't do anything.
Of course this can work only if used in suitable places of the formula, for example $a+\x{b+c}$ would have the right spacing after the first + (because of the empty subformula); the last empty subformula does nothing.
My opinion is still that bad breaks must be solved with suitably placed \nobreak commands.
Some examples:
\documentclass[a4paper,draft]{book}
\newcommand{\x}[1]{{}$\kern-2\mathsurround${}
\binoppenalty10000 \relpenalty10000 #1{}$\kern-2\mathsurround${}}
\begin{document}
\parbox{5cm}{
A formula \(a+\x{c+d}\)\break showing that spaces are right
A new formula \(a+\x{c+d}\) showing that spaces are right
A brand new formula x \(a+\x{c+d}\) showing that spaces are right
A brand new formula xx \(a+\x{c+d}\) showing that spaces are right
A brand new formula xxx \(a+\x{c+d}\) showing that spaces are right
A brand new formula xxxx \(a+\x{c+d}\) showing that spaces are right
Another brand new formula \(a+\x{c+d}\) showing that spaces are right
Right: $\sin(\x{a+b})$
Wrong: $\sin\x{(a+b)}$
\mathsurround=30pt
A formula xxxxxxx \(a+\x{c+d}\) showing mathsurround
A formula xxxxxxx \(a+c+d\) showing mathsurround
}
\end{document}
Addition about usage
The \x macro (possibly with a more descriptive name) should be used in specific places. Its contents must
(1) start with an ordinary symbol or be preceded by an ordinary symbol;
(2) end with an ordinary symbol or be followed by one.
It doesn't support the style declarations \displaystyle, \textstyle, \scriptstyle, or \scriptscriptstyle; it may make sense to carry a \displaystyle declaration, this might be done with a *-variant.
It doesn't support \left or \right: it's not allowed something like
$...\left(\x{a+b}\right)...$
but this is not a problem, as no formula can be split at relation or operation symbols between \left and \right and the spaces around these symbols never participates to stretching or shrinking.
Here's one way. The gap is controlled by the \setstackgap macro; The whole thing can be raised or lowered with a \raisebox; the number of dots in the stack are the space-separated argument of the stack.
Note: you could stack any characters as such, not just dots. If the [usestackEOL] option is passed to the package, the EOL separator is no longer a space, but a \\ character.
\documentclass{article}
\usepackage{stackengine}
%\stackMath
\setstackgap{S}{1pt}
\begin{document}
$A \Shortstack{. . . .}B$
$A \raisebox{-1.2pt}{\Shortstack{. . . . .}}B$
$A \setstackgap{S}{.5pt}\Shortstack{. . . . .}B$
\end{document}
Best Answer
Use
\limits:The above
^and below_parts may be empty, of course. This works also for\prodand\sum, for example (for all math operators to be exact).But as mentioned already in the comments: It's not always good to force some output, because the line height could get to big. You have to try with your document because we don't know your settings (font, font size, line height, etc).