- From: Neil Soiffer <soiffer@alum.mit.edu>
- Date: Thu, 7 Sep 2023 15:10:05 -0700
- To: "www-math@w3.org" <www-math@w3.org>
- Message-ID: <CAESRWkC-381i0Tc_=gPyZ5MHi=j4C+hrcTUfGMF86J19NTvD4A@mail.gmail.com>

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

Received on Thursday, 7 September 2023 22:10:24 UTC