Musings

The most recent version of Opera 9.50, is now claimed to have MathML support out of the box. What they’ve actually done is come up with a CSS stylesheet, which succeeds in giving a semblance of the correct appearance to many MathML constructs.

But, even with Opera’s fairly sophisticated extensions to the basic technology of CSS (e.g. the use of SVG background images), there are many things which simply don’t work. Most glaring are tensors. Consider the itex command, $$\tensor{R}{_i_^j_k_^l}$$. This produces

$$\tensor{R}{_i_^j_k_^l}$$

which looks like

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mmultiscripts>
    <mi>R</mi><mi>i</mi> <none/> <none/> <mi>j</mi> <mi>k</mi> <none/> <none/> <mi>l</mi>
  </mmultiscripts>
</math>

The Opera people have written up a “profile” of MathML, which is supported by their stylesheet. And, as you can see, tensor notation was one of the things they had to pitch overboard.

So I asked the author how one is supposed to mark up tensors in a fashion compatible with their profile. His response

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <msubsup>
    <mi>R</mi><mrow><mi>i</mi><mi> k</mi></mrow><mrow><mi> j</mi><mi> l</mi></mrow>
  </msubsup>
</math>

(there are other options too, like using mphantom or mspace instead of Unicode spaces)

was absolutely mind-blowing. He actually recommended changing the order of the tensor indices and then faking out the appearance of the correctly-ordered indices using spaces. You can imagine how that’ll work in assistive technology. And hypergeometric functions ($\multiscripts{_2}{F}{_1}$), for instance, are apparently too “marginal” to even be worthy of this ASCII Art treatment.

Chaals, the erstwhile accessibility guru, must be undergoing some serious cognitive dissonance.

I have plenty of other complaints about the proposed CSS-compatible Profile. But those’ll have to wait for some other post, as I’m nearly out of rant.

My immediate concern is elsewhere. Soon enough, users of Opera 9.50 are going to be visiting this site and, unlike in the past, they are going to assume that the formulæ they see are being rendered as intended.

So, before they start writing me about my boneheaded mathematical errors, perhaps I need to compose some popup warnings targetted at Opera users…