From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f7be1,be6b7e036aa9236c X-Google-Attributes: gidf7be1,public X-Google-Thread: 1014db,be6b7e036aa9236c X-Google-Attributes: gid1014db,public X-Google-Thread: fa0ae,be6b7e036aa9236c X-Google-Attributes: gidfa0ae,public X-Google-Thread: 11390f,be6b7e036aa9236c X-Google-Attributes: gid11390f,public X-Google-Thread: 1094ba,be6b7e036aa9236c X-Google-Attributes: gid1094ba,public X-Google-Thread: 101deb,be6b7e036aa9236c X-Google-Attributes: gid101deb,public X-Google-Thread: 1164ba,be6b7e036aa9236c X-Google-Attributes: gid1164ba,public X-Google-Thread: 103376,be6b7e036aa9236c X-Google-Attributes: gid103376,public From: ken@coho.halcyon.com (Ken Pizzini) Subject: Re: language wars (results 13 September) last posting Date: 1996/09/26 Message-ID: <52ebc2$59u@news1.halcyon.com>#1/1 X-Deja-AN: 185493781 distribution: inet references: <521ebg$k80@news1.halcyon.com> <528lab$6af@mill.gdls.com> organization: What, me? newsgroups: comp.lang.ada,comp.lang.apl,comp.lang.basic,comp.lang.c,comp.lang.fortran,comp.lang.perl.misc,comp.lang.pl1,comp.lang.rexx,comp.lang.pascal.misc,comp.lang.smalltalk Date: 1996-09-26T00:00:00+00:00 List-Id: In article <528lab$6af@mill.gdls.com>, Art Schwarz wrote: >Just to provide a basis for settling the discussion, why not contribute >your procedure to generate the appropriate statistics and contribute a >summary of the statistics. It seems that the conjecture that Friday the >13th (or any other day) occurs more frequently / less frequently than >anything is demonstrable, so demonstrate. > >To be more contentious, there have been 2 (?) postings of algorithms. >Before questions are levied on implementation or language features, >post an algorithm which demonstrates your case. I'm not sure, but I suspect that this posting was prompted by my ill-considered posting where I unfairly hinted at the possibility that someone's Smalltalk implementation was flawed. I was basing my claim on a mathematical proof, which unfortunately depended on a lemma which I failed to prove, and which turned out to be false. I canceled that article twice -- once shortly after posting, when I realized my error, and again after someone re-posted my article in an attempt to clean-up after a rogue canceler. For the benifit of other mathematically inclined calendar watchers, the lemma was that a 400-year interval had a number of days which is not divisible by 7. Other simple lemmata about the calendar and a dash of group theory would then show that the 13th of a month will be equidistributed across the days of the week over any multiple of 2800 years. (The "proof" I had would not rule out shorter periods, but the existence of such a period was sufficient for the question at hand.) Unfortunately for my proof, the number of days in any 400 year interval on the Gregorian calendar *is* a multiple of 7, and thus some other form of analysis is required to determine what the distribution of the days of the week that the 13th of a month fall on is. --Ken Pizzini