Subject: Re: [HM] Calendrical questions
From: Sanford Segal (ssgl@math.rochester.edu)
Date: Tue Feb 01 2000 - 12:57:21 EST
It is funny how rumors get started! With respect to (2) below, the
necessary information is in Fraenkel's autobiography Lebenskreise. Shortly
after his 16th birthday Fraenkel write his first published paper, which
obtained a formula for the date of Passover in the Islamic calendar. This
appeared in 1908 (Fraenkel was born in 1891). In autumn 1909 Fraenkel
completed a far deeper calendrical study, which thanks to Alfred Loewy, who
was not only a mathematician, but Fraenkel's uncle by marriage, appeared in
Crelle. These publications leaned on the "Method of Gauss". (pp.76-77).
Through a letter from Loewy and the Crelle paper (which was about the date
of Easter), Fraenkel met Kurt Hensel (p.110). He wrote a dissertation with
Hensel in ring theory and this also appeared in Crelle. Its title was "On
Zero-Divisors and the Decomposition of Rings". He was awarded the doctoral
degree in January 1914 summa cum laude.(pp. 119-120).
While Fraenkel's autobiography is not always historically reliable, I
think we can trust it on the events of his life.
Sandy Segal
> (1) Forgive me if this question has already been discussedd on this list;
> if so I missed it, and it seems timely to bring it up. As we all know, on
> the 29th of February we will experience a once-in-400-years event: the
> addition of a leap day in a century year. That century years are not leap
> years unless divisible by 400 is a correction called metemptosis (as I
> learned some 5 years ago from a post of John Conway to another history
> list), and many sources, including a recently published book on calendrical
> calculations that I examined at the AMS meeting last week in Washington,
> claim that that correction is the *only* difference between the Julian and
> Gregorian calendars. But Conway's post mentioned another correction, called
> proemptosis, that occurs in a century year usually once every 300 years,
> but every eighth time at an interval of 400 years. Conway gave a formula
> for determining in which years proemptosis occurs, but did not specify
> precisely what the correction *is*. Is it also the addition (or perhaps
> subtraction) of a single day? If so, which day? In particular, what
> happens in years when both corrections occur?
>
> (2) I understand that the doctoral dissertation of Abraham Fraenkel, the
> well-known set theorist, concerned a method for computing the date of
> Passover (presumably an improvement over the methods in use before). Has
> his method been published, and is it still the preferred one?
>
> Thanks to any and all who can provide enlightenment on these matters.
>
>
> Dr. John W. Dawson, Jr.
> Professor of Mathematics
> Penn State York
> 1031 Edgecomb Avenue
> York, PA 17403 U.S.A.
>
> Tel.: 717-771-4131 (work)
> 717-846-1225 (home)
> FAX: 717-771-8404
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