Reconsider the way pseudo-operators (like `\sin`) are rendered

[tmke8]

Ideally, we'd do something like

<math>
  <mi>x</mi>
  <mpadded lspace="0.16667em" width="+0.33333em"><mi>sin</mi></mpadded>
  <mi>θ</mi>
</math>

which does work in MathML 3 (and hence Firefox) but not in MathML Core.

[tmke8]

This works in Firefox and Chrome:

<math display="block">
  <mi>x</mi>
  <mpadded lspace="0.16667em" width="+0.33333em" style="width: calc-size(min-content, size + 0.33333em)">
    <mi>sin</mi>
  </mpadded>
  <mi>θ</mi>
</math>

As of 2026-01-28, WebKit has not decided on a position on this feature. (Firefox is supportive but hasn't implemented it yet.)

EDIT: however, this doesn't actually really work in Firefox because Firefox can't display accents right above <mpadded>:

<math display="block">
    <mi>x</mi>
    <mover accent="true">
        <mpadded lspace="0.16667em" width="+0.33333em" style="width: calc-size(min-content, size + 0.33333em)">
            <mi>cos</mi>
        </mpadded>
        <mo stretchy="true">̂</mo>
    </mover>
    <mi>θ</mi>
</math>

[tmke8]

Temml, btw, renders x\cos\theta as

<math display="block" class="tml-display" style="display:block math;">
  <mrow>
    <mi>x</mi>
    <mrow>
      <mspace width="0.1667em"></mspace>
      <mi>cos</mi>
      <mo>⁡</mo> <!-- U+2061, FUNCTION APPLICATION -->
      <mspace width="0.1667em"></mspace>
    </mrow>
    <mi>θ</mi>
  </mrow>
</math>

[tmke8]

One thing to consider is this: \cos^2 \theta. I believe the space should appear after the superscript and not before it.