What makes a mathematical document accessible?
Structural integrity
A document has structural integrity if each component within it retains the structure originally given to it by the author, even when transformed to another format or interacted with using technology. For instance, when an author writes a fraction they define the numerator and denominator. A format with structural integrity retains the association between these and the fraction to which they belong.
Inadequate structure
A document has inadequate structure if it is not possible for software to distinguish parts of the document and the association between those parts. For example, a document may have inadequate structure if an author has created headings by making the text larger and bold. Visually these look like headings but it is not possible for a computer to recognise this text conclusively as a heading. This is a general example, not specific to mathematics.
- A mathematical document may, in addition, have inadequate structure because the way the mathematical content has been input is inappropriate.
- Microsoft Word, and many other methods of encoding mathematical content, do not enforce adequate structure. The author must ensure this.
Lossy transforms
It is possible to start off with adequate structure encoded in a document format but to lose this via a transformation. The most important example of this, for mathematics, is any transform to PDF. PDF is a lossy format for mathematics as the structure of the equations is not retained.
Alternative methods of interacting with material
Some examples of inaccessibility are not due to lack of structure but are because the material is presented in a mode that is fundamentally inaccessible to a particular group of readers. For instance, a diagram which does not have an alternative method of accessing the information contained within it.
- It is up to the author to provide appropriate alternative modes of interacting with material.