2 Theorems and stuff

You will notice that there are a variety of ways that theorem type environments are presented in the different formats. All of these pass technical accessibility tests or are following RNIB Clear Print guidelines and have been used for at least a decade in our provision for disabled students. We have also take on feedback that in HTML formats colour might be helpful to show where environments start and finish. We have chosen to impose a structured colour scheme on you, for now. The colours have been chosen so that they pass accessibility tests for contrast with the text.

However, this doesn’t mean we have got it right. Give us feedback. Ideally, get students to give feedback too.

Theorem 2.1: (Foo)

This is a theorem environment already provided by Bookdown. It still works as before.

Proposition 2.2: (Thingy we need for 2.1)

However, in this system you can now

  • Change the numbering system of the inbuilt environments - this is done in the file _bookdown.yml. Please see the file in the same folder as this file.
  • Reference other environments within names. Notice that you need to use a double backslash.
Proof: (Of theorem 2.1)

You can make new unnumbered theorem environments. You can call them whatever you like. They work kind of like the inbuilt ones but the environment is always newtheorem and the env defines the type.

You need to have predefined the type and made any changes to the standard print style in the file _bookdown.yml. Please see the file in the same folder as this file.

You can’t control what things look like in the other formats as they have been designed with a variety of accessibility features. If you don’t like how they look then maybe contact us and ask about it. It might be something we can think about changing or allowing author control or, it might not.

Proof (Proof of theorem 2.1).

Defining your own proof environment doesn’t stop the inbuilt one working.

Definition 2.1:

You can leave some things numbered on their own.

Definitions 2.2:

You can create new numbered theorem types. Unlike inbuilt environments, for them to be numbered in all formats they must have a label. If you forget then they won’t be numbered in any format except for PDF and then your numbering won’t match. I might try and fix this at some point. You can number them alone or with other inbuilt or newtheorem environments.

You need to have predefined the type, the numbering and made any changes to the standard print style in the file _bookdown.yml. Please see the file in the same folder as this file.

Take care not to reuse the inbuilt numbering labels with your new theorems! This will lead to odd things happening. The inbuilt labels to avoid are: thm, lem, cor, prp, cnj, def, exm, exr, fig, tab and eq.

References still work in the same way as in Bookdown. Now go to theorem 2.1 or proposition 2.2.

Here is some text which is not part of the below example.
Examples:
You can turn off the colour and padding in html, ePub and Word for any newtheorem or inbuilt theorem type. You do this in the _bookdown.yml file by adding the theorem name to the colouroff style_with list.

Here is some text which is not part of the above example.