MathML - left subscript and superscript

Question

How to write left subscript and superscript preserving correct syntax of MathML? I mean something like this:

Thanks for the hints.

Answer 1

Use <mmultiscripts> - see http://www.w3.org/TR/MathML3/chapter3.html#presm.mmultiscripts for details. In your case, it's:

<mmultiscripts>
    <mi>a</mi>
    <mprescripts/> <mi>c</mi> <mi>b</mi>
</mmultiscripts>