**Short answer:**

The following command sequence inserts a `\medskip`

in your document, you just have to bind it to the shortcut you prefer: `inset-insert vspace medskip`

.

**General answer:**

At times it is a bit tricky to figure out what LyX commands one actually has to bind to a shortcut to achieve the desired behavior. While for most commands LyX shows the last executed command in the status bar, this does not help for commands that open a dialog for further settings. In the following, I describe the approach I used to figure this one out, so you could apply it for other questions in this respect:

(1) Start Lyx with the `-dbg action`

option (that is, run `/path/to/lyx-binary/lyx -dbg action`

from a console window).

(2) Execute the command for which you want to figure out the command sequence. LyX lists the actions in the debug output in the console. The following shows the relevant output for *Insert->Formatting->Vertical Space...* with selecting *MedSkip*:

```
LyXFunc::dispatch: cmd: action: 219 [dialog-show-new-inset] arg: 'vspace' x: 0 y: 0
LyXFunc.cpp(771):
LyXFunc::dispatch: cmd: action: 218 [dialog-show] arg: 'vspace vspace defskip' x: 0 y: 0
LyXFunc.cpp(1842): dispatch msg is
LyXFunc.cpp(1875): verbose dispatch msg (dialog-show-new-inset vspace)
LyXFunc.cpp(771):
LyXFunc::dispatch: cmd: action: 224 [inset-apply] arg: 'vspace medskip' x: 0 y: 0
LyXFunc.cpp(771):
LyXFunc::dispatch: cmd: action: 225 [inset-insert] arg: 'vspace medskip' x: 0 y: 0
```

(3) Usually the last command executed by some dialog-based action is the one you are looking for. In this case it is the line with `[inset-insert]`

and the arguments `vspace medskip`

.

(4) Use the LyX Mini-Command Buffer (View -> Toolbars -> Command Buffer) to manually test the command: `inset-insert vspace medskip`

If the result is what you want to achieve, you are done and have found the command sequence to bind to the shortcut. Otherwise you have to experiment more :-)

**Update: General answer using the GUI only**

For those who do not feel comfortable with starting LyX from a console window, there is also a GUI-only way to figure out the commands (thanks to Dominik for the hint!):

(1a) In LyX, open the debug Console by selecting *View –> Message Pane*

(1b) Configure the settings on the *Settings* page, so that *User commands* and *External control interface* are set to *Yes*:

(2) Switch on the *Output* pane and execute the command for which you want to figure out the command sequence. The following shows the relevant output for *Insert->Formatting->Vertical Space...* with selecting *DefSkip*:

(3) Proceed as above.

`minipage`

s (and `\parbox`

es) are known to have issues with baseline skips. It's easy enough to avoid them in order to obtain what you want (marked **B** below). If you must use a `minipage`

, then consider adding some `\strut`

s *without* the `v`

ertical `skip`

s (marked **C** below). **A** is the original input provided, while the last set of comparisons shows the similarities between **B** and **C**.

```
\documentclass{article}
\usepackage[margin=1in,landscape]{geometry}
\begin{document}
\noindent
\begin{minipage}[t]{.45\textwidth}
\noindent \textbf{A: Calculation of the edge length of the octagon} \\
\noindent \begin{minipage}[t]{4.5in}
\vskip0pt
\noindent \raggedright{The sum of the measures of (interior) angles in the octagon \\
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior) \\
angles is $135^{\circ}$. The angles that are supplementary to the \\
(interior) angles of the octagon all have the same measure \\
--- $45^{\circ}$. So, the four right triangles at the corners of the \\
square are isosceles right triangles. If $x$ is the edge length \\
of the octagon,}
\end{minipage}
\end{minipage}
\hfill
\begin{minipage}[t]{.45\textwidth}
\noindent\textbf{B: Calculation of the edge length of the octagon}
\noindent\raggedright The sum of the measures of (interior) angles in the octagon
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior)
angles is $135^{\circ}$. The angles that are supplementary to the
(interior) angles of the octagon all have the same measure
--- $45^{\circ}$. So, the four right triangles at the corners of the
square are isosceles right triangles. If~$x$ is the edge length
of the octagon,
\end{minipage}
\bigskip
\noindent
\begin{minipage}[t]{.45\textwidth}
\noindent \textbf{A: Calculation of the edge length of the octagon} \\
\noindent \begin{minipage}[t]{4.5in}
\vskip0pt
\noindent \raggedright{The sum of the measures of (interior) angles in the octagon \\
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior) \\
angles is $135^{\circ}$. The angles that are supplementary to the \\
(interior) angles of the octagon all have the same measure \\
--- $45^{\circ}$. So, the four right triangles at the corners of the \\
square are isosceles right triangles. If $x$ is the edge length \\
of the octagon,}
\end{minipage}
\end{minipage}
\hfill
\begin{minipage}[t]{.45\textwidth}
\noindent\strut\textbf{C: Calculation of the edge length of the octagon}
\begin{minipage}[t]{4.5in}
\noindent\strut\raggedright The sum of the measures of (interior) angles in the octagon
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior)
angles is $135^{\circ}$. The angles that are supplementary to the
(interior) angles of the octagon all have the same measure
--- $45^{\circ}$. So, the four right triangles at the corners of the
square are isosceles right triangles. If~$x$ is the edge length
of the octagon,
\end{minipage}
\end{minipage}
\bigskip
\noindent
\begin{minipage}[t]{.45\textwidth}
\noindent\textbf{B: Calculation of the edge length of the octagon}
\noindent\raggedright The sum of the measures of (interior) angles in the octagon
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior)
angles is $135^{\circ}$. The angles that are supplementary to the
(interior) angles of the octagon all have the same measure
--- $45^{\circ}$. So, the four right triangles at the corners of the
square are isosceles right triangles. If~$x$ is the edge length
of the octagon,
\end{minipage}
\hfill
\begin{minipage}[t]{.45\textwidth}
\noindent\strut\textbf{C: Calculation of the edge length of the octagon}
\begin{minipage}[t]{4.5in}
\noindent\strut\raggedright The sum of the measures of (interior) angles in the octagon
is $(8 - 2)180^{\circ} = 1080^{\circ}$, and so, the measure of the (interior)
angles is $135^{\circ}$. The angles that are supplementary to the
(interior) angles of the octagon all have the same measure
--- $45^{\circ}$. So, the four right triangles at the corners of the
square are isosceles right triangles. If~$x$ is the edge length
of the octagon,
\end{minipage}
\end{minipage}
\end{document}
```

A drawback of using `minipage`

s is that it doesn't break across the page boundary since the content is boxed.

## Best Answer

This picture is

slightly differentto the OP's one. The suggestions given below are used. The LaTeX code generated by LyX (with a few lines deleted) is:First, looking at your LaTeX code, as Torbjørn T. and David Carlisle mentioned, the increased vertical space between the line containing "Veech [4]" and the multiline environment comes from a new line. In LyX you can make end of paragraphs visible under "Tools > Look & Feel > Display" otherwise the new line is invisible. Anyway, put the cursor directly after the

`s`

in "Veech [4] defines" and pressDeleteonce to delete the new line. Note (or messure) that the distance between the baselines of "Veech [4]" and "K_0(\theta)" is thesameas the distance between "K_1(\theta)" and "We have, corresponding...".Second, looking into my crystal ball I tend to see

that the LaTeX code and the picture do not match, that is, for the picture the new lines in front of and after the multiline environment were removed;

that the font size is set to "Large" for parts of your document (or your entire document?) (font size "Large" in LyX corresponds to

`\large`

in LaTeX, as "Larger" corresponds to`\Large`

...);that the line spacing is set to "Double".

that matching parentheses / delimiters were forgotten.

Not sure whether all points are true; just my guess. My suggestions are

(In LyX, there is also "View Source" to see the generated LaTeX code.) If there were a mismatch, maybe update the question.

Instead of using "Large" font size, "Reset" the font size to use "Normal" font and change "Fonts > Base Size" under "Document > Settings..." to 12pt. The default size corresponds usually to 10pt. Hence, the font size will not change ("10pt + \large = 12pt", see also here) but the width of the document will be adjusted differently for 12pt.

There are several rules in typography to make a text look better, although one might object to them at first. LaTeX (well, LyX is generating LaTeX code) knows about them and thinks some space around display math (e.g. multiline environment) looks better. This could also be a reason.

You have operators like "sum" in the formulas. Instead of using

`(`

and`)`

you should consider using delimiters in math mode. (Use "Insert > Math > Delimiters" or simple the short cuts`Alt+M`

`(`

or`Alt+M`

`<`

...). Then the parentheses will be scaled and also some (a tiny) space will be inserted. Especially, this should be done with the ||norm||. Otherwise how to read your formula: this way`| b |n| |n\theta| |`

or that way`|b| n ||n\theta||`

??