Re: ÷ vs :

Thank you for this background note, Neil.   Very interesting.

Stephen

P.S.  I am avidly following these discussions, even if I have had a
standing conflict with the meeting time.   The meeting time conflict on
Thursdays will continue until December since I am teaching on Thursdays in
our slot.

On Thu, Sep 7, 2023 at 6:11 PM Neil Soiffer <soiffer@alum.mit.edu> wrote:

> On the call today, we discussed issue 473
> <https://github.com/w3c/mathml/issues/473> which is about what intent
> values should be used with differentiation. In it, Deyan brings up division
> which led to a discussion of ÷ and : for division -- something that led to
> some surprising differences amongst attendees. After the meeting, Deyan
> mentioned Cajori's book on the history of math notations and how ÷ actually
> was originally an alternative to "-" for minus.
>
> I read a bit more and on p272, Cajori writes "There are perhaps no symbols
> which are as completely observant of political boundaries as are ÷ and : as
> symbols for division. The former belongs to Great Britain, the British
> dominions, and the United States. The latter belongs to Continental Europe
> and the Latin-American countries... Such statements would not apply to the
> symbolisms for the differential and integral calculus, not even for the
> eighteenth century."
>
> I thought perhaps the decimal separator was another instance, so I looked
> to see what Cajori wrote. His book was published in 1929. He said that in
> the US, "." came to become the standard after about 1850. Something I never
> knew is that the centered dot was used by many to mean both multiplication
> and decimal separator because that meant the decimal separator wouldn't be
> confused with a punctuation ".". Apparently, that was the case in Great
> Britain in 1929. And of course, ","  was used in other countries. I'm glad
> to see that the Brits came to their senses since then :-)
>
> As always, Cajori is an interesting read for those who want to know
> something about the history of math notation. It is also a reminder that
> math notation is an evolving topic. It gives a little comfort to me that if
> we don't get the naming of intents right, we will be in good company for
> not getting it right the first time.
>
>     Neil
>
>
>