en

Nightly PDFs -> http://nightly.learnyou.org/lysa

Learn You Some Algebras for Glorious Good!

This is a fun, easy-to-read, free and open source math textbook. You can read all about it at http://www.learnyou.org. (Sorry, I'm too cheap to pay for an SSL certificate, so no HTTPS).

Links, in alphabetical order

• Book outline
• Book website
• Contributing guide
• IRC Channel
• Issue tracker
• LaTeX style guide
• /r/lysa on Reddit
• Main author's email: [email protected]
• Nightly PDFs
• Russian translation

Contributing

Getting set up

Installing the needed software

This is separated by operating system. At the moment, LYSA has only been built on Linux and BSD. I haven't tried OS X or Windows, simply because I don't have access to them.

• Arch: Open a terminal, run the following command

  sudo pacman -S git texlive-bibtexextra texlive-fontsextra \
      texlive-latexextra texlive-langextra
  

• Gentoo: Run this command in a terminal:

  sudo emerge -jav dev-vcs/git dev-tex/biblatex \ 
      dev-texlive/texlive-latexrecommended \
  

  Warning: This will spawn a ton of processes, but will make the build a lot faster (from several hours to a few minutes). If your memory is precious, use -av instead of -jav.

  Warning: These instructions are pretty old, and I don't have access to this OS any more. Forgive me if the instructions don't work any more.

• Debian <7: Cannot be built with standard configuration

  The version of TeXLive is too old to build LYSA. You need at least TeXLive 2014. The version shipping with Wheezy (Debian 7) is TexLive 2012. You would need to manually install TeXLive 2014, and then build LYSA.

• Debian >=8: Run this in a terminal:

  sudo aptitude install git texlive-bibtex-extra \
      texlive-fonts-extra texlive-latex-extra texlive-latex-recommended \
      texlive-math-extra 
  tlmgr init-usertree
  tlmgr --usermode install newtxmf
  

• FreeBSD: I haven't been able to build LYSA on FreeBSD, but I'm not a FreeBSD expert. Here's what I tried:

  sudo pkg install texlive-full git
  tlmgr --usermode init-usertree
  tlmgr --usermode install newtxmf
  

• Mac OS X: I don't use, nor do I have access to Mac OS X, so I don't know how to build LYSA on Mac OS X. Sorry. If you know how, don't be shy to add instructions!

• Ubuntu <= 12.04: Run this command in a terminal:

  sudo aptitude install biblatex texlive texlive-latex-extra \
   texlive-bibtex-extra texlive-math-extra texlive-latex3
  

  Warning: These instructions are pretty old, and I don't have access to this OS. (These instructions were added by someone else). Forgive me if they don't work any more.

• Ubuntu 14.04

  sudo aptitude install texlive-latex-extra texlive-math-extra \
    texlive-fonts-extra latexmk texlive-bibtex-extra xzdec
  tlmgr init-usertree
  tlmgr --usermode install newtxsf
  

• Windows: I don't use, nor do I have access to a machine running Windows, so I don't know how to build LYSA on Windows. Sorry. If you know how, don't be shy to add instructions!

Cloning & Building

Run these commands in a terminal

git clone https://github.com/learnyou/lysa.git
cd lysa
git submodule init
git submodule update
make

You can then read lysa-en.pdf

You can use ./watchbuild.sh if you have inotify installed, and it will rebuild the book whenever there's a change to any of the files.

If you've never used Git

git is a version control system. Basically, it allows us to have logs of the changes people make to LYSA. git has a legendarily poor interface, so don't feel bad if you have a hard time using it. Despite its poor interface, it is actually a very nice program, which is why everybody uses it.

I highly recommend reading Chapter 2 of the Git book if you haven't already, because it covers basic configuration and usage of Git.

Ideally, you would read the entire book, but I don't think anyone is actually going to do that.

Adding Content

The English version of the book is written in a markup language called LaTeX. LaTeX is pretty easy, so you can probably pick it up just from reading the source for the book. If you have any trouble, consult that link.

If you add a substantial amount of new content, such as a new chapter, or a new section, please feel free to add yourself to the \author field in book/lysa.ltx (you don't have to, if you don't want to). If you suggested changes, or made a number of trivial changes, you can add yourself to the \editors field.

Graphs and Code

• For the time being, you can generate a graph with anything you want, as long as it's open-source. You just have to include the code to generate the graph (in case we want to change it). I recommend Sage.

• Code examples should be written with Sage, though.

Committing

Try to make sure that each commit only contains one change. It's a lot less annoying to have to sift through 20 commits each with 1 different change than 1 commit with 20 different changes. If the change is difficult to summarize in one line, then you should probably split up the commit with git add -p.

When in doubt, follow the Erlang OTP Git Commit Guide.

Sources

The sources are listed in the book/bibliographies/lysa.bib file. Here are some suggested readings:

• Abstract Algebra, from Wikibooks
• Foundations of Analysis, by Edmund Landau
• The Foundations of Analysis, by Larry Clifton
• Algebra, by Thomas W. Hungerford
• Linear Algebra Done Right, by Sheldon Axler
• Set Theory, by Thomas Jech
• Foundations of Analysis, by Joe Taylor

LaTeX Style Guide

LaTeX is the markup language I use for LYSA. It's very good for math. This document details the style choices you should make when writing LaTeX.

1. Editor

   You can use pretty much any text editor for LaTeX. Emacs is particularly good for LaTeX. Here is my LaTeX-mode-hook

   (rainbow-mode 1)
   (rainbow-delimiters-mode 1)
   (flyspell-mode 1)
   (wc-mode 1)
   (hl-highlight-mode 1)
   
   (setq-local fill-column 80)
   (setq-local indent-tabs-mode nil)
   (setq-local tab-width 4)
   (setq-local tab-stop-list (number-sequence 4 80 4))
   (setq-local evil-shift-width 4)
   
   (define-key evil-insert-state-map (kbd "`") 'self-insert-command)
   (local-set-key (kbd "RET") 'reindent-then-newline-and-indent)
   
   (setq-local LaTeX-item-indent -2)
   (setq-local LaTeX-indent-level 4)

2. Line length

   Wrap lines to a reasonable limit, somewhere within 70-80 characters. I use 80, personally

3. Indentation

   Indentation is 4 spaces, except in cases where other indentation makes more sense. Take, for example, bibliography entries:

   @book { lyah
         , author    = {Miran Lipova\v{c}a}
         , title     = {Learn You a Haskell for Great Good!}
         , publisher = {No Starch Press}
         , year      = {2011}
         , address   = {245 8th Street, San Francisco, CA, 94103}
         }
   
   @online { jobs-programming
           , title   = {steve jobs on programming}
           , url     = {https://www.youtube.com/watch?v=5Z1gfgM7kzo}
           , urldate = {2015-01-01}
           }

   Listing environments get 4-space indentation, but 2 for \items:

   \begin{enumerate}
     \item Stuff
       More stuff
   \end{enumerate}

   But other environments get normal indentation:

   \begin{alignedmath}
       p, q \in B \\
       p = q \\
       \evalat{\arc{f}}{p} \ne \evalat{\arc{f}}{q} \\
   \end{alignedmath}

   Put your macros in lysa.ltx.

   Don't use tabulator charactors.

   Display math should use either

   • the equation environment
   • one of the math environments in lysa.ltx

   Do not use $$...$$, the displaymath environment, or \[ ... \]

4. Exercises

   Exercises should use either:

   a. The ExerciseList environment:

   ```latex
   \begin{ExerciseList}
       \Exercise{What is the result of
           \begin{equation}
               \mset{0,1} \times \mset{2,3}
           \end{equation}
       }
   
       \Answer{The result is the set of ordered pairs between the two sets, so:
           \begin{equation}
               \begin{array}{rcl}
                   \mset{0,1} \times \mset{2,3} & = & \{\,   \mlist{0,2} \\
                                                &   & \comma \mlist{0,3} \\
                                                &   & \comma \mlist{1,2} \\
                                                &   & \comma \mlist{1,3} \\
                                                &   & \}                 \\
               \end{array}
           \end{equation}
       }
   \end{ExerciseList}
   ```
   

   b. The ExcList environment, which wraps an ExerciseList in a \subsubsection.

File hierarchy

This is a non-exhaustive guide to the file hierarchy:

lysa/                               Repository
  en/                               English version of LYSA
    README.md                       This document
    OUTLINE.md                      The outline
    book/                           The actual book
      lysa.ltx                      The top node of the book.
      lysabuild                     The script to build the book
      chapters/                     The individual chapters
        X-something.ltx             Chapter X top node
        X/                          Chapter X sections
      appendices/                   The appendices
      bibliographies/               The bibliography
      graphs/                       Sage-generated graphs, along with the source code
        buildgraphs                 A program to build all of the graphs
        foo.sage                    Source file for a graph
        foo.sage.py                 Intermediate code generated by Sage (should be .gitignore'd)
        foo.png                     The graph itself
        foo-bar.png                 Maybe another variant of the graph
      images/                       Other images
      tex/                          Other TeX libraries imported