Making a space before and after a word in LaTeX

Question

I have the following in LaTeX:

v_{i}=\frac{ 1}{ n}\sum_{j=1}^{n}\left(\mu_{ij} \right)^{m}x_{j}\hspace where\hspace n_{i}=\sum_{j=1}^{n}\left(\mu_{ij}\right)^{m}

How can I make a space before and after where?

I tried \hspace, but seems didn't work.

The \hspace macro takes an argument: \hspace{<length>}. For example: \hspace{.5em} or \hspace{2cm}. Also, you shouldn't use text in math-mode. After loading the amsmath/amstext package, you can use \text{ where }. — Qrrbrbirlbel, Dec 03 '13 at 20:35

score 6 · Answer 1 · answered Dec 03 '13 at 20:32

6

Rules of thumb:

Never type text in math mode.
Never type math in text mode.

Your code can be written in two ways:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[ v_{i}=\frac{ 1}{ n}\sum_{j=1}^{n}\left(\mu_{ij} \right)^{m}x_{j} \text{ where } n_{i}=\sum_{j=1}^{n}\left(\mu_{ij}\right)^{m} \]
\end{document}

or

\documentclass{article}
\begin{document}
Inline math looks like $v_{i}=\frac{ 1}{ n}\sum_{j=1}^{n}\left(\mu_{ij} \right)^{m}x_{j}$ where $n_{i}=\sum_{j=1}^{n}\left(\mu_{ij}\right)^{m}$.
\end{document}

answered Dec 03 '13 at 20:32

marczellm

11,809

2

Of course, \left and \right in that formula are wrong. – egreg Dec 03 '13 at 20:33
@egreg and the parentheses might be unneeded too. In this case, \left and \right only change the position of the superscript, is that that bad? – marczellm Dec 03 '13 at 20:38
Yes, the result is poor. – egreg Dec 03 '13 at 20:40
@marczellm. Thanks for your reply. I'm interested in the first form. I tried it, but still not having the spaces – Simplicity Dec 03 '13 at 20:48
@Simplicity Note that the spaces are inside the \text{ where }, just next to the {}. If you need more space, do use \quad or even \qquad. – marczellm Dec 03 '13 at 20:55
@egreg Are you suggesting the \left and \right are not necessary? Please edit my answer if necessary. – azetina Dec 03 '13 at 21:18

score 5 · Accepted Answer · edited Apr 13 '17 at 12:34

Some standard spacing in math mode include \quad or \qquad but using \hspace{<length>} is possible:

enter image description here

\documentclass[letterpaper]{article}
\usepackage{mleftright}
\usepackage{amsmath}
\begin{document}
\[
v_{i}=\frac{1}{n}\sum_{j=1}^{n}\mleft(\mu_{ij} \mright)^{m}x_{j}\quad \text{where}\hspace{2em} n_{i}=\sum_{j=1}^{n}\mleft(\mu_{ij}\mright)^{m}
\]
\[
v_{i}=\frac{1}{n}\sum_{j=1}^{n}\left(\mu_{ij} \right)^{m}x_{j}\quad \text{where}\hspace{2em} n_{i}=\sum_{j=1}^{n}\left(\mu_{ij}\right)^{m}
\]
\end{document}

The MWE above illustrates the effects of the use of \left and \right. For that, you can consider using the mleftright package by Heiko Oberdiek:

The package defines variants \mleft and \mright of \left and \right, that make the delimiters act as \mathopen and \mathclose. These commands address spacing difficulties in subformulas.

Read Spacing around \left and \right for an interesting discussion about this.

Making a space before and after a word in LaTeX

2 Answers2