Re: What's the intent for ":"?

Hi Neil,

I'm focusing on the single "ratio" in the latter half of your email. As you
say, the legal concept annotation is intent="ratio".
Selecting explicit English prepositions should be done via a literal, i.e.
intent="_to" or intent="_for". Similarly the empty literal override for
time would be intent="_".
In those cases we could enforce speech, but will lose the concept
information.

Similarly for Bulgarian prepositions: one can choose between the literals
intent="_към" or intent="_за", but the concept is still intent="ratio",
which is localized intent="съотношение", with a possible alias name
"отношение".

I think being disciplined about the distinction between (mathematical)
concepts and (language) literals is one of the lifelines we have available
in making these decisions, while retaining a clear naming scheme.

Some additions:
1. The wikipedia page on ratio[1] suggests that one can also encounter the
notation "a to b" directly, where one would assume an <mtext>to</mtext> in
MathML, possibly with wrapping spaces.  So a Braille reader may also
encounter the "to" word directly as text.

2. Wikipedia also provides an alternative readout of a ratio when the
context is a "proportion", i.e. an equality between two ratios. In "a:b =
c:d" the left-hand side "a:b" can be narrated "a is to b", where the "c:d"
right-hand side can also be narrated "c is to d", with the connecting "="
read "as".

In an AT that wants to provide specialized readings for proportion, one
could imagine recognizing a wrapping mrow property <mrow
intent=":proportion">.
Or alternatively, having a pattern that recognizes infix use of "=" where
both arguments can be identified as ratios.
On the argument level, AT can either try to detect the infix use of <mo
intent="ratio">:</mo>, or cases where the argument is wrapped with a
property, as in <mrow intent=":ratio">.
The wrapping mrow could be a helpful technique for something harder to
detect such as the n-ary ratio "2 : 4 : 8 : 16".

I think embracing the "progressive enhancement" spirit could be healthy in
this kind of ladder of ever increasing annotation burden. Does the
completely raw MathML get narrated well? If yes, leave as-is. If not,
annotate the innermost nodes that encounter issues. If the speech remains
unnatural at places, gradually climb up the subtrees, depositing properties
and compound intent expressions, until the desired outcome is achieved.

Greetings,
Deyan

[1] https://en.wikipedia.org/wiki/Ratio

On Thu, Jul 27, 2023 at 9:30 PM Neil Soiffer <soiffer@alum.mit.edu> wrote:

> I think everyone would agree that ":" is ambiguous. It's one of the few
> cases where the braille Nemeth code (but not UEB) cares about the meaning.
>
> Here's a case I came across:  3:30
>
> It certainly could be a ratio. Or it could be a time. In normal use, there
> might be more context to help (3:30 = 1:10 or 3:30pm). However, when
> standing alone, there is no way to know.
>
> I think both ratio and time are common enough to be in core. Probably also
> function definition (f: x → y) is in core along with "such that" ({x:
> x>0}).
>
> As per the discussion today (and times in the past), the intent should be
> on ":" when possible. However, ":" is a case where it doesn't work out
> well. One can force the speech (e.g., "intent='to' for ratio or intent=' '
> for time). But how does the braille know that 'to' means it is a ratio and
> should output the braille for ratios instead of the braille for a
> punctuation ":"?
>
> Aside: listening to Khan Academy, "to" is used in something like "3:2" but
> "for" or "for every" is used in the videos when there are quantities/units
> given as in "3 dogs : 2 cats". So here you would use intent="for" -- so
> saying AT should know that "to" used on ":" means ratio is not going to
> work.
>
> I think this is a case where pushing intent to the operator doesn't work
> despite it being an infix operator and it needs to be on the mrow. Being in
> core, an intent value of "ratio" could be spoken as "to" by AT, but still
> recognized easily when generating braille.
>
> Thoughts?
>
>     Neil
>
>