Require complete sets to remain inside one MathML element

[abcdsen-create]

Priority: High

Description

Document
that a set must not be split between MathML and ordinary paragraph text. Both
braces, the set elements, and any natural-language condition must remain inside
one continuous <math> element. If the closing brace is outside the
MathML, the expression may not be recognized as a set at all.

Recommended markup

<math
xmlns="http://www.w3.org/1998/Math/MathML">

<mi>A</mi><mo>=</mo><mo>{</mo><mi>x</mi><mo>∣</mo><mi>x</mi>

<mtext>is a champion in the years 2011–2015</mtext>

<mo>}</mo>

</math>

Acceptance criteria

• Guidance explicitly requires matching opening and closing braces within the same <math> element.
• Natural-language conditions are shown inside <mtext>.
• An incorrect split-markup example and its expected speech failure are documented.