Re: [EXTERNAL] Re: Minutes: MathML Core meeting July 27, 2020

On 28/07/2020 19:55, Murray Sargent wrote:
> David’s case
>
>  <mrow><mo>|</mo> zzz  <mo>|</mo> zzz <mo>|</mo></mrow>
>
> is a bit bizarre. How would you speak it? Do the outer |’s mean “absolute value”? In which case, what’s the inner | mean? I’ve struggled with the ambiguities of the vertical bar over the years. It’s true that with clever parsing of the <mrow>, you can figure out that the first | is an opener, the middle is binary of some sort and the final | is a closer. This example is clearly for illustration only, since it doesn’t appear to represent a mathematical construct.
>
> But getting back to my expectation-value example, how do you know what the vertical bars in ⟨Ψ|ℋ|Ψ⟩ mean? Are they separators or absolute values? As a physicist, I’d recognize this expression as a quantum mechanical expectation value and know that the vertical bars are separators, but without that context, the vertical bars have to have an attribute like separator=”true” to be unambiguous.

yes my last example is meaningless so hard to vocalize.

the point is though that the fence=true in mathml3 doesn't affect the 
spacing just a hint to speak the expression. The unfinished semantic 
attribution proposals for mathml4 would have something like

<mrow semantics="quantum mechanical expectation(#1,#2,#3)">

   <mo> ⟨</mo>

<mi arg=1">Ψ</mi>

<mo>|</mo>

<mi arg="2">ℋ</mi>

<mo>|</mo>

<mi arg="3">Ψ</mi>

<mo>⟩ </mo>

</mrow>

so you really know its the quantum mechanical expectation with those 
three parameters and you can pronounce it however you need. (there are 
several proposals for the exact syntax of the new semantics attributes 
but they all aim to give the same information here.)



so that

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