# Tags explained

## The tag system

Each tag refers to a unique item (section, lemma, theorem, etc.) in order for this project to be referenceable. These tags don't change even if the item moves within the text.

## How to use it?

To find the tag for an item, you can look in the URL or use the toggle between tags and numbers, or you can read it off from the pdf file. See below for LaTeX instructions on how to reference a tag.

The tag system provides stable references to definitions, lemmas, propositions, theorems, remarks, examples, exercises, situations and even equations, sections and items. As the project grows, each of these gets a tag which will always point to the same mathematical result. The place of the lemma in the document may change, the lemma may be moved to a different chapter, but its tag always keeps pointing to it.

If it ever turns out that a lemma, theorem, etc. was wrong then we may remove it from the project. However, we will keep the tag, and there will be an explanation for its disappearance (in the file tags mentioned below).

## How to reference tags

@misc{kerodon,
}
\cite[\href{https://kerodon.net/tag/000E}{Tag 000E}]{kerodon}
This can be changed according to your tastes. In order to make the \url and \href commands to work, one should use the hyperref package.