Discussion, talk and tips
https://forum.puppylinux.com/
Is there a LaTex editor available in the FatDog repository?
https://en.m.wikipedia.org/wiki/LaTeX
If not, is there one you could recommend?
Not sure if Geany is able to handle LaTex and compile the final PDF... 
No and no to your questions. To be exact, the LaTeX format is pure text, so you could edit LaTeX with geany or any other text editor. However, I suspect you're looking for a LaTeX WYSIWYG editor that will show graphical output from _compiled_ LaTeX, for which you need a TeX distribution. There are packages for that, but not in the Fatdog repo.
We used to package Lyx for this purpose but like @step said, it's not much use unless one has LaTex installed, so we no longer do that today.
I have revived lyx for Fatdog64. You will have to wait a couple of days to find the package in Gslapt. Lyx can run without LaTeX installed, but you need LaTeX for output and exports, such as PDF. For LaTeX and fonts and language files, you need to install texlive separately, you're on your own with that. In 2019 I got texlive running in Fatdog64-8xx fairly quickly by mounting the ISO and running tlman (texlive manager) according to the texlived installation instructions. Since the installed texlive is huge, you may consider installing it all in one folder on an external disk. You could follow the instructions for portable texlive.
For starters read Reasons to use Lyx instead of LaTeX and make your call.
I thought that TinyTeX could be a valid alternative to texlive. However, based on this request for help I seriously doubt that it can work in a useful manner. It is probably too stripped down for LyX.
Some followers of this thread may be interested in another document formatting program similar to LaTeX which is much smaller. The program is lout 3.43
I have never used this program myself but have read about it. The program used to be in the Debian repositories but was removed because there was no longer any Debian maintainer and there were two outstanding security risks.
Since that time "William8000" has released lout 3.43 which he claims addresses those issues plus other minor bugs.
Producing an lout SFS for FatDog is way beyond my capabilities but if anyone is interested I started my search by googling
Lout Document Formatting System
and also looked up
https://github.com/william8000/lout
cheers,
superchook
Thanks, guys! Will have a look at the mentioned Lyx repository.
I am currently using VerbTex on Android in order to write my LaTeX documents and create the final PDF, which is compiled on a server in the cloud:
This has the advantage that you do not have to worry about the setup of the server that compiles the final PDF and you can simply call the available packages on the server in your local LaTeX document. The downside is that some LaTeX modules are not available and VerbTex is not able to process local images in your final PDF. Since Android 11, the storage location of an app is not accessible for local users, so that you are not able to link to a locally stored image in your LaTeX document.
So it would be great to have a LaTeX editor in FatDog that is able to compile the final PDF, include local images that I create with PlantUML and allow to install additional LaTeX packages.
A couple of options that I found so far that seem to be popular:
https://www.xm1math.net/texmaker/
https://texstudio.sourceforge.net/
https://vim-latex.sourceforge.net/
Not sure if anyone has experience with one of those options.
I came back to this thread to list yet another alternative, in the class of LyX: TeXmacs. Unlike LyX, and in spite of the "TeX" name prefix, TeXmacs doesn't need TeX or LaTeX for output. They provide an AppImage and a static binary for Linux. I couldn't get the AppImage to work (but I'm pretty sure it can work given the right system configuration). The static binary worked out of the box. I played with it ten minutes, inserted a mathematical visual formula, exported to PDF, which opens OK and displays the formula as mathematical text. This seems like a very good program.
It has a LaTeX inport function as well, but I didn't play with it.