[Tex/LaTex] When should we use a blank line

best practicesspacing

I only know that we have to make at least one blank line between two adjacent paragraphs.

My question is:

What is the proper way to make use of a blank line ?

For example:

Is it recommended to make a blank line between heading command call, e.g. \chapter{}, and the first text content as follows?
```
\chapter{Introduction}

In this chapter we ....
```
or
```
... that is proven true.

\chapter{Limit}
```
Is it recommended to make a blank line between two consecutive display equations as follows?
```
\[ \sin x \] 

\[ \cos x \]
```
Is it recommended to make a blank line between a sentence and a display equation as follows?
```
Assume we have

\[
  \cos x
\]
```
or
```
\[
  \cos x
\]

that satisfies ...
```
etc…

Edit 1:

How about \bigskip, \vspace{}? Does each of them needs one blank line before and one blank line after as follows:

Yes. This is a book.

\bigskip

Commander, please open the silo!

Yes. This is a book.

\vspace{1km}

Commander, please open the silo!

Best Answer

I can tell you what I'd do in these 3 cases:

1.: After \chapter{} and similar command I'd always use a blank line as it makes the document structure clearer. Moreover, "In this chapter ..." is the start of a paragraph.

2.: I wouldn't use a blank line here if both displays belong to the same paragraph. However, I usually wouldn't use two consecutive displays at all; I'd use align* or gather* instead.

3.: In that particular case don't use blank lines as everything is within one paragraph. Speaking of clarity of the document structure, I'd say that

Assume we have    
\[
  \cos x
\]
that satisfies ...

is clear enough. Only use a blank line after the display if the paragraph ends after the display.

4.: As for your extra question about vertical spacing commands: In the context you provide, I'd always surround them with blank lines for clarity of the document structure. I sometimes use them before a display like this; then you mustn't put a blank line:

... some text
\vspace{-1ex}
\[
  ...
\]

I should point out that manual corrections like in this last example are rarely needed, and you should only use them if you're sure that you know what you're doing.

Related Solutions

[Tex/LaTex] When should one use \begingroup instead of \bgroup

\bgroup is a synonym for {, which is defined in Plain TeX using \let\bgroup={.

It interacts with TeX's "digestive system" in hairy ways: {s and \bgroups start the same sort of groups, called simple groups, and each can be terminated with either }s or \egroups, since they are the same. But when the TeX digestive system encounters them, they are of different catcodes, so commands that look ahead, e.g., in LaTeX with \section\bgroup Title}, can break this matching.

\begingroup is different. It is a TeX primitive, and it matches a different sort of group that TeX accounts for separately, called "semi-simple groups" (a Knuth joke, I assume). Thus a \begingroup must be terminated by an \endgroup, not a }, and vice versa for \endgroup.

I generally avoid \bgroup, and use \begingroup, but \bgroup could be useful if you are messing about with a nested token list.

[Tex/LaTex] When should I use non-breaking space

In general where the break will create orphans that would distract the reader.

Some less obvious examples:

I~am
I~definitely
mod~1


The matching $(AW,BX,CY,DZ)$ is unstable, because for example
$A$ prefers~$Z$ to~$W$ and at the same time $Z$ prefers~$A$ to~$D$.
But the matching $(AZ,BW,CX,DY)$ is stable;

(we say that girl~$h$ rejects the proposal)

step~A2 stops when $P$ has nobody left to propose~to,
but step~B2 keeps making redundant proposals ad~infinitum when

The details of Algorithm~B

has local probability~${1\over n}$,

The "I am", "I definitely" etc., is a bit controversial, but personally like a lot of other people don't like "I" at the end of a line break.

Edit 1:

Best Answer

Related Solutions

[Tex/LaTex] When should one use \begingroup instead of \bgroup

[Tex/LaTex] When should I use non-breaking space

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