September 2015 - mathfun@mailman.xmission.com

[math-fun] Polya urn model
by James Propp 27 Sep '15

27 Sep '15

Does anyone have a pointer to the cute way of seeing that the Polya urn model gives rise to the uniform distribution at the nth level, by contriving a uniformly random permutation of 1,2,...,n whose first (or last) element corresponds to the number of white-vs.-black balls at the end? Jim Propp

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[math-fun] "Shakespeare" programming language
by Henry Baker 27 Sep '15

27 Sep '15

"A program written in Shakespeare looks like the text of a Shakespearean play, while also fulfilling all of the obligations of a Turing complete programming language; that is, given infinite memory and time, a Shakespeare program can be written that replicates the functionality of any program written in any other language." Code snippet: "Thou art as sweet as the sum of the sum of Romeo and his horse and his black cat! Speak thy mind!" http://motherboard.vice.com/read/know-your-language-coding-toil-and-trouble…

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Re: [math-fun] something linguistic
by Wouter Meeussen 26 Sep '15

26 Sep '15

with thanks to Hans: similar pronounciation or perfect match (pron. & orthography = ****) ware :: where way / weigh :: whey we'll / weal :: wheel we'r :: whir weald / wield :: wheeled weather / wether :: whether **** wen :: when **** wet :: whet **** witch :: which wig :: whig (??) **** wile :: while **** wiled :: whiled **** wine :: whine **** word :: whirred wit :: whit **** wither :: whither **** wye :: why cute language you have, difficult to write it is! Wouter. -----Original Message----- From: Hans Havermann Sent: Friday, September 18, 2015 4:56 PM To: Wouter Meeussen Subject: Re: [math-fun] something linguistic http://www.cooper.com/alan/homonym_list.html Scroll down to the W.

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Re: [math-fun] Something linguistic
by Warren D Smith 25 Sep '15

25 Sep '15

HAJ=HAJJ=HADJ recently came up in the news, although perhaps it should be regarded as cheating to use alternate spellings of the same word, e.g. ANALYSE=ANALYZE, since that would be too logical. If they have to be different words, then "Z" might not be trivial? Nah, PHIZ=FIZZ and related machinery still handles Z.

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[math-fun] Collapsing groups with enough random relations
by Allan Wechsler 25 Sep '15

25 Sep '15

I started a discussion on this general topic, that was unfortunately embedded in an earlier one about a specific question about a group modeled on English homophony. I'm sending this message to avoid a confusing half-threadjacking. I'm not sure I understood Dan's proposed probability weighting. What I think I would have done is chosen a parameter lambda between 0 and 1, and imagined a process generating random relations by starting with 1 and multiplying on the right by a randomly-chosen letter, then exiting with probability lambda, otherwise going back to stick on a new letter. If lambda is high, most of these relations will be short; if lambda is low, most will be long. We expect that it takes more relations to collapse the group if the relations are long.

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Re: [math-fun] Something linguistic
by Warren D Smith 25 Sep '15

25 Sep '15

Oh, and of course, this great intellectual accomplishment should be summarized under the title "The triviality of English."

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Re: [math-fun] math-fun Digest, Vol 151, Issue 54
by Warren D Smith 25 Sep '15

25 Sep '15

Re the claim F and R and V uncovered, STAPH=STAFF TUFF=TOUGH so FF=1, and PHIZ=FIZZ and PHI=FI so (using P=1, H=1, Z=1 from before) F=FF so F=1 TOR=TORR so R=1. Wait a minute, did I forget about X? SAX=SACKS, TAX=TACKS. So... the only remaining holdout is "V". If you were to allow German pronunciations V=W or V=F but that seems to be cheating. So we may have to settle for the trivial group, except that V is nontrivial. (And I guess somebody should compile the best proof from the ingredients.) -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)

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Re: [math-fun] Something linguistic
by Warren D Smith 25 Sep '15

25 Sep '15

BAIT=BATE and since E=1 already shown, we see I=1, and then RODE=ROAD so A=1 RUDE=RUED proves some kind of commutativity, LOWED=LOAD so W=1, HOUR=OUR so H=1, FLOWER=FLOUR so U=1, SKULL=SCULL and QI=KI and SIC=SICK so K=C=Q=1, GNU=NEW and SIGN=SINE so G=1, PSI=SIGH so P=1, DAMN=DAM so N=1, HYMN=HIM so Y=1, CAN'T=CANT so aprostrophe=1, WRAP=RAP so R=1 , PLUMB=PLUM and CLIME=CLIMB so B=1, PASS=PAS so S=1, HICCOUGH=HICCUP so P=1 (given previous results), WOOD=WOULD so L=1 in view of previous results, WHAT=WATT hence T=1, MUMM=MUM so M=1, GIN=JINN, so G=J so J=1, PASSED=PAST or GUESSED=GUEST (?) would prove D=1 (since T=1) if accepted... oh, just AD=ADD shows that, SOX=SOCKS so X=1 in view of previous results which also is shown by FAUX=FOE, so if I am counting right, this takes care of every letter, plus apostrophe, except that the following letters remain open: V,Z

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Re: [math-fun] Cool orbit trajectory
by Warren D Smith 25 Sep '15

25 Sep '15

> From: Henry Baker <hbaker1(a)pipeline.com> > https://www.youtube.com/watch?t=2&v=BIy5g4bvskM > This is a visualization of the trajectory designed by the ACT-ISAS team that > won 1st place in the GTOC8. > The theme chosen by NASA / JPL for the 8th edition of the GTOC was > “high-resolution mapping of radio sources in the universe using space-based > Very-Long-Baseline Interferometry (VLBI)”. Three spacecraft had to depart > from the Earth and needed to perform several interferometric measurements of > one of 420 radio sources. An interferometric measurement could be made when > the three spacecraft lay on a plane whose normal pointed towards the radio > source. Moon gravity assists and low-thrust propulsion had to be used to > target each interferometric measurement. --I don't understand. OK, first of all, if a bunch of radio telescopes receive a signal (and let me assume they each record the signal along with ultra-accurate record of the time), then cannot they do "interferometry" algorithmically later REGARDLESS of whether they lie in a plane normal to the line to the source, they can do it in pretty much any geometry at all. No? And there is no need for the telescopes to be in real time communication with each other, which in any event would be rather problematic if they were a million miles apart, under that assumption. [The best atomic clocks have accuracies of order 1 part in 10^17 or 10^18 now, which seems fully adequate for all this.] So, either I'm confused, or NASA is. > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > math-fun mailing list > math-fun(a)mailman.xmission.com > https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun > > > ------------------------------ > > End of math-fun Digest, Vol 151, Issue 49 > ***************************************** > -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)

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[math-fun] Fwd: [xbbn] simulation (with visualization) of celestial bodies? Matlab?
by Allan Wechsler 25 Sep '15

25 Sep '15

This came up on a group of ex-BBN employees, and since orbital mechanics is a topic that comes up occasionally here, I thought I would forward it to you guys. Eva, I'm CC-ing you to keep you in the loop; I hope I am not doing anything wrong by forwarding your request to a group with similar interests. ---------- Forwarded message ---------- From: Eva Hudlicka <hudlicka(a)ieee.org> Date: Fri, Sep 25, 2015 at 2:36 PM Subject: [xbbn] simulation (with visualization) of celestial bodies? Matlab? To: xbbn(a)googlegroups.com Hi all Looking for some help setting up a simulation (in Matlab?) of some celestial bodies interactions. Specifically, a simulation of a planetary orbit with several suns - with the following parameters to play with: # of suns (up to a point), initial location of suns and planet, and mass of all bodies. Maybe this already exists somewhere? Thanks for any info. Best Eva ---------------- Eva Hudlicka, PhD Psychometrix Associates, Inc. School of Computer Science - U.Mass.-Amherst psychometrixassociates.com https://www.cs.umass.edu/faculty/directory/hudlicka_eva -- You received this message because you are subscribed to the Google Groups "xBBN" group. To unsubscribe from this group and stop receiving emails from it, send an email to xbbn+unsubscribe(a)googlegroups.com. To post to this group, send email to xbbn(a)googlegroups.com. Visit this group at http://groups.google.com/group/xbbn. For more options, visit https://groups.google.com/d/optout.

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