[Tex/LaTex] Smashoperator for the vertical space

amsmathmath-modemath-operatorsmathtools

I would like to vertically smash a summation sign in a way that the line has a vertical space as if the summation sign wouldn't be there.

To illustrate it please see the MWE. The space between the first and second line should be the same as the space between the third and fourth line. At the moment it looks like the second line doesn't belong to the first one.

Note: I cannot write the last column into one line, because the second column will contain more text in the end and I have to break the last column into two or multiple lines.

MWE:

\documentclass{scrbook}
\usepackage{amsmath}

\begin{document}
\begin{alignat}{3}
        &   \sum_{m \in M}  x_m     && = 1      & \quad &   , \forall m \in M \colon a \neq b ;                     \notag  \\
        &                                                                   &&              &               &   \phantom{,{}}   c \neq d                                                                \\
        &                                                       x_m     && = 1      &               &   , \forall m \in M \colon e \neq f ;                     \notag  \\
        &                                                                   &&              &               &   \phantom{,{}}   g \neq h            
\end{alignat}
\end{document}

Best Answer

You can use \smash[b]:

\documentclass{scrbook}
\usepackage{amsmath}

\begin{document}
\begin{alignat}{2}
\smash[b]{\sum_{m \in M}}\, x_m &= 1\quad && , \forall m \in M \colon a \neq b ; \notag \\
                                &         && \phantom{,{}}   c \neq d \\
               x_m              &= 1      && , \forall m \in M \colon e \neq f ; \notag  \\
                                &         && \phantom{,{}}   g \neq h
\end{alignat}
\end{document}

Instead of \, you could use

\mathop{\smash[b]{\sum_{m \in M}}}

but it's more complicated with no real advantage other than inserting the thin space automatically.

I'd not left align x_m, but if you really want, you know how to do it.

Instead of the phantoms you could add another set of columns.

enter image description here

Note that using \smash alone would also remove the height, which is not desired here.

Related Solutions

[Tex/LaTex] reduce vertical space for \xrightarrow

Remedied the valid comment of mh256, creating macro \xxrightarrow[]{} that reduces the space of the underset, but allows for the length of the underset.

EDITED to make it \mathrel and also to use temp \box2 instead of \box0, which appears to be also used by \xrightarrow.

\documentclass{minimal}
\usepackage{amsmath,stackengine}
\stackMath
\newcommand\xxrightarrow[2][]{\mathrel{%
  \setbox2=\hbox{\stackon{\scriptstyle#1}{\scriptstyle#2}}%
  \stackunder[0pt]{%
    \xrightarrow{\makebox[\dimexpr\wd2\relax]{$\scriptstyle#2$}}%
  }{%
   \scriptstyle#1\,%
  }%
}}
\parskip 3pt
\begin{document}
\fbox{$\xxrightarrow[\fbox{below}]{\fbox{above}}$}

\fbox{$\xxrightarrow[\fbox{below is a long text}]{\fbox{above}}$}

$ x \xxrightarrow[bottom]{top} y$

$x \xxrightarrow[a]{a} y$

$x \xrightarrow[a]{a} y$

\end{document}

enter image description here

[Tex/LaTex] Line Break in Equation with Text

Use gathered:

\documentclass[10pt,a4paper]{article} 
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage[margin=1.5cm,left=1.5cm,right=1.5cm,top=6cm,bottom=2cm,includefoot,headsep=.8in]{geometry}
\usepackage{amsmath}

\begin{document}
\begin{equation}
    \textit{Outperf.-Point} =
        \frac{\left(
            100\% +
            \frac{
                % Note: removed redundant parentheses
                \textit{Coupon p.a.}\times\textit{Days of Accrued Interest}
            }{365} -
            \textit{Offer-Price}
        \right)\times
        \textit{Notional Amount}}
        {\textit{Conversion Ratio}} + 
        \begin{gathered}
            \textit{Price of} \\
            \textit{the Underlying}
        \end{gathered}
\end{equation}
\end{document}

I’ve also tidied up your code a bit: don’t use italicized numbers and parentheses.

I also add the output, so you can readily check whether it is what you asked for:

Addition

Too much vertical space between “Price of” and “the underlying”? Then try

\documentclass[10pt,a4paper]{article} 
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage[margin=1.5cm,left=1.5cm,right=1.5cm,top=6cm,bottom=2cm,includefoot,headsep=.8in]{geometry}
\usepackage{amsmath}

\begin{document}
\begin{equation}
    \textit{Outperf.-Point} =
        \frac{\left(
            100\% +
            \frac{
                % Note: removed redundant parentheses
                \textit{Coupon p.a.}\times\textit{Days of Accrued Interest}
            }{365} -
            \textit{Offer-Price}
        \right)\times
        \textit{Notional Amount}}
        {\textit{Conversion Ratio}} + 
        \begin{gathered}
            \textit{Price of} \\[-\jot]
            \textit{the Underlying}
        \end{gathered}
\end{equation}
\end{document}

And here’s the new output:

Second Addition

Of course, as @egreg suggests, it is even easier to use a tabular environment, like this:

\documentclass[10pt,a4paper]{article} 
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage[margin=1.5cm,left=1.5cm,right=1.5cm,top=6cm,bottom=2cm,includefoot,headsep=.8in]{geometry}
\usepackage{amsmath}

\begin{document}
\begin{equation}
    \textit{Outperf.-Point} =
        \frac{\left(
            100\% +
            \frac{
                % Note: removed redundant parentheses
                \textit{Coupon p.a.}\times\textit{Days of Accrued Interest}
            }{365} -
            \textit{Offer-Price}
        \right)\times
        \textit{Notional Amount}}
        {\textit{Conversion Ratio}} + 
        \begin{tabular}{@{}c@{}}
            \textit{Price of} \\
            \textit{the Underlying}
        \end{tabular}
\end{equation}
\end{document}

The corresponding output, once again:

Note that the contents of the tabular would not scale with the math style, e.g., if used in superscript (but the contents of gathered would not either). Should this ever become necessary, it can be done.