Tags explained

Every chapter, section, definition, statement, remark and labelled equation of My Automorphic Project has a tag: a four-character code such as 0007. A tag always points to the same mathematical item. The item may be renumbered, moved to another section or to another chapter, but its tag never changes. This is what makes it safe to cite the project while it is still growing.

The idea, and the format of the tags, are taken from the Stacks project.

Finding a tag

Each item shows its tag in the box at the side of its page. If you know a tag, type it in the search box at the top of any page to go straight to the item.

Citing a tag

Put this in your BibTeX file:

@misc{my-automorphic-project,
  author       = {The {My Automorphic Project} authors},
  title        = {\textit{My Automorphic Project}},
  howpublished = {\url{https://automorphic.ramonmn.com}},
  year         = {2026},
}

and cite an item by its tag, for example

\cite[\href{https://automorphic.ramonmn.com/tag/0007}{Tag 0007}]{my-automorphic-project}

The \url and \href commands need the hyperref package. The box at the side of every item contains this line with the right tag filled in.

How tags are assigned

A tag is a string of four characters, each a digit or a capital letter other than O (to avoid confusion with zero). Tags are handed out in order, starting from 0001.

The assignments are recorded in the file tags/tags of the project, one per line:

0007,example-definition-adeles

Here 0007 is the tag, and the identifier after the comma says that it points to the item labelled definition-adeles in the chapter example. When an item is renamed or moved, only the identifier on its line changes. If an item is ever removed from the text, its tag is retired and never used again.