HDTenEightyP/NetNews huggingface dataset:
From: egs@cs.Princeton.EDU (Emin Gun Sirer)
Subject: Re: GST registration number check digit: puzzle and prize
Originator: egs@volkl
Reply-To: egs@cs.Princeton.EDU (Emin Gun Sirer)
Organization: Department of Computer Science, Princeton University
Date: Thu, 31 Dec 1992 23:28:52 GMT

dave@lsuc.on.ca (David Sherman) writes:
>Virtually all businesses in Canada are registered for the Goods and
>Services Tax (GST) and receive a registration number, which is "R"
>followed by nine digits.
>
>Included in the 9 digits is a check digit.  Revenue Canada Excise,
>which administers the GST, refuses to release the formula for the
>check digit, stating that it "relates to an internal procedure for
>verifying registration numbers".

>R123965659	R130134310	R111046959
 [other examples elided to please inews]


	I believe the last digit is the checksum and and is calculated
according to Luhn's formula. This is the exact same technique used in
computing the last digit of credit card numbers.

	The last digit is equal to the ten's complement of the sum of twice
each digit modulo ten. Last time this came up in sci.crypt, someone posted
the following piece of code to calculate them [code appended at the very end].

	Here's a check:
;a.out 12396565 12142551 12159807 11019143 13013431 11104695
12396565 - 9
12142551 - 6
12159807 - 2
11019143 - 4
13013431 - 5
11104695 - 9
;a.out 10097678 12156037 11104695 10635306
10097678 - 6
12156037 - 9
11104695 - 9
10635306 - 3

	I'll go one step forward and contend that the 130134310 is a typo
(or perhaps a typo on the part of the receipt publisher or perhaps is not
very readable). 

	There really is nothing magical about this formula, but knowing
it, one could construct credit card numbers (and perhaps GTEs) that seem
valid.

Gun.
#include <stdio.h>
/*
 * >     I am looking for any pointers to information on the algorithms used
 * >to verify credit cards (and similar authentication schemes).  For example,
 * >I know that the last digit on most credit cards is typically a checksum.
 * >What is this method actually called?  Is is a commercial standard?
 * 
 * It is called Luhn's formula.  The last digit is the ten's complement of
 * the modulo sum of the other digits where each other digit is doubled.
 * There is an international standard specifying the number codes, and
 * their allocation.  The following routine will calculate the checksum 
 * number:
 */
/*
 * Return last digit of a bank card (e.g. credit card)
 * Receives all the digits, but the last one as input
 * By Diomidis Spinellis <dds@doc.ic.ac.uk>
 */
int bank(char *u) {
        register i, s = 0;
        int l, t;

        l = strlen(u);
        for(i = 0; i < l ; i++) {
                t = (u[l - i - 1] - '0') * (1 + ((i + 1) % 2));
                s += t < 10 ? t : t - 9;
        }
        return 10 - s % 10;
}

void main(int argc, char *argv[]) {
    int i;
    if(argc <= 1) {
	fprintf(stderr,"Usage: %s bankcardno\n", argv[0]);
	exit(1);
    }
    for(i = 1; i < argc; ++i)
	printf("%s - %d\n", argv[i], bank(argv[i]));
    exit(0);
}
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Newsgroups: rec.puzzles
Subject: Re: Direction of the sun
Date: 25 Dec 1992 15:37 CST
Organization: Texas A&M University, Academic Computing Services
Distribution: world
NNTP-Posting-Host: zeus.tamu.edu
News-Software: VAX/VMS VNEWS 1.41    

potamian@hpl.hp.com (Spyros Potamianos) writes...
>>A points to the sun and says:
>>"This is the direction where the sun is right now."
>>B replies:
>>"But don't you know that the rays take over 8 minutes to reach the Earth?
>>The sun is actually already below the horizon."
>>Which is correct?  Why? (Make it understandable to a ten year-old.)
>># note: ignore subsidiary points like refraction by the atmosphere.

Also ignoring the motion of the earth around the sun which displaces
the sun's direction slightly in the opposite direction (I think).

>Now, let's go to a "solarcentric" system.
>The sun is still, positioned again at (d,0) and the earth is at (0,0)
>rotating counterclockwise (around itself, *not* around the sun!)
>with an angular velocity 'w'.
>An observer standing on the earth (assume a zero earth radius, after all
>it's very small compared with 'd') uses a different system of coordinates
>X'Y'. 

>As you can see, its velocity has a non zero Y component. The photon will
>appear to be coming from an angle:
>    a = arctan( v'y/v'x ) = arctan (sin(w*d/c)/cos(w*d/c)) 
>      = arctan(tan(w*d/c))
>      = w*d/c
> 
>I.e. the sun will appear being at an angle 'w*d/c' "above" its current
>position, a result consistent with the one we got from the "solarcentric"
>system (BTW, this angle is around 2 degrees)

The sun actually _is_ at an angle w*d/c above the direction which you
are calling 'its current position'. I.e. it is not stationary in the
X'Y' coordinates.

Dave Ring
dwr2560@zeus.tamu.edu
From: clong@romulus.rutgers.edu (Chris Long)
Newsgroups: rec.puzzles
Subject: Re: Answers to Hard Analogies
Date: 22 Dec 92 12:59:39 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

In article <BzC36E.1x0@cantua.canterbury.ac.nz>, Bill Taylor writes:

>> 2. Mountain : Plain :: Acrocephalic : ?

>> 2. Homalocephalic

>> Acrocephalic is having a pointed head; homalocephalic is having a flat head.

> What about PLATYCEPHALIC ?

_Taber's Cyclopedic Medical Dictionary_ tells me this means having a
wide skull, but it also says that platycephaly is a flattening of the
skull.  _The American Pocket Medical Dictionary_, 13th edition, says
that platycephalous means having a wide, flat head.  Ambiguous, but
it looks okay.  Anyone care to jump in?
-- 
Chris Long, 265 Old York Rd., Bridgewater, NJ  08807-2618

"S.B., with an I.Q. of 161, failed to complete his course of study,
running away instead with his professor's wife."
H. J. Eysenck, _Know Your Own I.Q._
Newsgroups: rec.puzzles.crosswords
From: sjm@bcrki65.bnr.ca (Stuart MacMartin)
Subject: Re: CWC27 Entries
Organization: Bell-Northern Research Ltd., Ottawa, Canada
Date: Wed, 23 Dec 1992 13:38:44 GMT

In article <1992Dec22.223613.22853@ulysses.att.com> guy@ulysses.att.com (Guy Jacobson) writes:
>A very good batch of clues this week, for both words.

Indeed!  I didn't come up with a clue for either.

>**See through pants arent bad with redhead inside (11)
>
>A saucy and delicious clue.  "Redhead" for R is a bit of a cliche,
>but it works in this clue.  The winner, by Anil Nair.

This joins my list of favourite clues from this group.
In fact, I only have one other:
  The cocoa-lover effuses over this.
(But that one was disliked by some.  To each his own!)
>________________________________________________________________
>
>*Stark woman with a divine chest turned over to receive a back rub and
> some pecker down under (10)

Really, Tom!  Even I would hesitate to say this one!
Appeals to my sense of naughtiness while being topical too.
Can't write this one down in my list of favourite clues, though, because
the list is at work and this clue is against regulations! :-)

"Pecker" does not need to be a woodpecker, IMO.

Stuart
--
: Stuart MacMartin                                    email: sjm@bnr.ca      :
: Bell-Northern Research                              phone: (613) 763-5625  :
: PO Box 3511, Stn C, Ottawa, K1Y-4H7, CANADA    Standard disclaimers apply. :
From: reid@ss6.cps.msu.edu (Dr Richard J. Reid)
Newsgroups: rec.puzzles.crosswords
Subject: PD Software for Crossing Words?
Date: 31 Dec 92 17:14:54 GMT
Organization: Department of Computer Science, Michigan State University
NNTP-Posting-Host: ss6.cps.msu.edu
Originator: reid@ss6.cps.msu.edu

Do you know of any PD software, preferably in C, that accepts
a list of words and lays them out as crossed words suitable
for a puzzle?

Alternatively, a reference to an algorithm more effective than
exhaustive search would be helpful.

Thanks,

Dick
Newsgroups: rec.puzzles.crosswords
From: levin@world.std.com (Levin F Magruder)
Subject: Favorites from this group
Organization: The World Public Access UNIX, Brookline, MA
Date: Fri, 25 Dec 1992 15:14:40 GMT

Stuart MacMartin writes:
>In article <1992Dec22.223613.22853@ulysses.att.com> guy@ulysses.att.com (Guy Jacobson) writes:

>>**See through pants arent bad with redhead inside (11)

>This joins my list of favourite clues from this group.
>In fact, I only have one other:
>  The cocoa-lover effuses over this.
>(But that one was disliked by some.  To each his own!)

I've missed a couple months of postings recently, so if the subject
of favorites has come up, sorry.

I'd list two others:
Every other letter an 'A': Bananas.
Jack, Queen, King, Snap.

I think both were submitted with exclamation points, but I don't see
why they're needed in either case.

I know the validity of the cocoa-lover clue was discussed extensively,
partly by me... but if anyone still wants to talk about it, I still
want a thorough explanation of the mechanics.  I seem to remember, by
the way, that the author agreed that, under American rules, it needs
Newsgroups: rec.puzzles.crosswords
From: guy@ulysses.att.com (Guy Jacobson)
Subject: CWC27 Winners
Date: Tue, 22 Dec 1992 22:26:16 GMT
Organization: AT&T Bell Laboratories

The winning clues for CWC27 are:


    See through pants arent bad with redhead inside (11)


by Anil Nair <nair@quintus.com> for the first word, and


    Senselessly bar auk, rook, and kingfisher from Australia (10)


by Tovah Hollander <tovah@onion.salad.mssm.edu> for the second.

I really like both clues, but because the second word was harder (and because
Tovah was the runner-up for the first clue), I am inviting her to moderate
CWC28 at her convenience.

-- 
_________________________________________________________________
Guy Jacobson   (908) 582-6558              AT&T Bell Laboratories
        uucp:  {att,ucbvax}!ulysses!guy	   600 Mountain Avenue
    internet:  guy@ulysses.att.com         Murray Hill NJ, 07974
Newsgroups: rec.puzzles.crosswords
From: bob@cullen.demon.co.uk ("robert f. gregory")
Newsgroups: rec.puzzles.crosswords
Subject: Newcomer to rec.puzzles.crosswords
Date: 3 Jan 93 17:33:37 GMT
Reply-To: bobg@cullen.demon.co.uk
Organization: cullen crosswords
X-Mailer: Simple NEWS 1.90 (ka9q DIS 1.19)

I have just come onto the net through the demon.co.uk gateway in London.

I head a small team of compilers and we handle thematic crosswords for a
number of public and in-house magazines and a few newspapers.

If someone had a collection of back messages from rec.puzzles.crosswords
on file and could EMail them to me so that I could pick up the background
of this group - clue-ing competitions and any other trails - I'd be
grateful.

Thanks in anticipation

Regards

Bob Gregory
Cullen Crosswords
19, Cyncoed Place
Cardiff CF2 6SG      Email bobg@cullen.demon.co.uk
Voice +44 222 759562
Newsgroups: rec.puzzles.crosswords
From: tovah@panix.com (Tovah Hollander)
Newsgroups: rec.puzzles.crosswords
Subject: CWC28
Keywords: competition, CWC, cryptic
Date: 24 Dec 92 20:33:05 GMT
Organization: PANIX Public Access Unix, NYC


Guy wrote:

>I really like both clues, but because the second word was harder (and because
>Tovah was the runner-up for the first clue), I am inviting her to moderate
>CWC28 at her convenience.

Unfortunately, my convenience is going to make the judging period for
CWC 28 somewhat lengthy, as I am off on vacation tomorrow and won't be
back until after New Year's.  However, I'm hoping that many of the rest
of you have similar plans, so I'm going ahead with this.

Also, in compensation for the delay, I'm giving you a special bonus
third clue to work on!

And so, on to ...


         CLUE WRITING COMPETITION NUMBER 28

Welcome to the Clue Writing Competition 28 (devised by Ian Gent).  The
rules, and this article, are much the same as used in earlier rounds.

The dates for CWC 28 are:

  Thursday  7 Jan 1993  23:59 EST   Deadline for CWC28 entries
  Friday    8 Jan 1993              I'll post the CWC28 winners
  Friday    8 Jan 1993              I'll post an annotated list of entries.

The rules:

Later on in this posting you'll find two words or phrases.  The first 
is chosen to be fairly easy to write a clue for; the second is intended 
to be more awkward.  

You may submit clues for either or both words.  I will accept only one
clue per person for each word; If you send more than one for a word, I
will accept the first one I receive.  E-mail the clues, along with your
name and e-mail address, clear explanations of how your clues work, and
whether or not you could run the next contest, to me at the following
address:

             tovah@onion.salad.mssm.edu (preferable) -OR-
	     tovah@panix.com

After the deadline, I'll pick my favorite clue for each word; thus
there will be two winning clues.  I'll pick my favorite of these two as
the overall winner, inviting its writer to set the next round of this
competition.  I'll post separately a list of runner-up clues, and all
the remaining clues, with as much commentary as I see fit.

IMPORTANT: Please DO NOT post your own clues, or anything else that
might give away the answer words!  Some readers of this group want to
try solving the winning clues; please don't spoil it for them.

The words for CWC28 follow, "rot13" encoded for extra security,






















ERFBYHGVBA

RCVCUNAL


Special Holiday Bonus
---------------------

	Jevgr n guveq pyhr (sbe bar bs gur gjb jbeqf nobir
	be sbe nal jbeq lbh pubbfr) vapbecbengvat n fcbbarevfz (r.t.,
	PNHTUG FJBEQ/FBHTUG PUBEQ be UVG N TANG/XAVG N UNG).  Gung vf,
	gur pyhr vgfrys fubhyq unir n pyrne naq frafvoyr fhesnpr ernqvat,
	ohg fubhyq or hafbyinoyr jvgubhg svefg "svkvat" gur fcbbarevfz.
	Sbe rknzcyr:
			Ybfg gnfgr sbe genafsre (5)

	Nsgre punatvat "ybfg gnfgr" gb "gbffrq ynprq" jr unir na nantenz
	sbe "qrpny" (n genafsreerq cvpgher).


Happy holidays, one and all!

-- 
Tovah Hollander
tovah@panix.com -or- tovah@onion.salad.mssm.edu
Newsgroups: rec.puzzles.crosswords
From: boek@mullian.ee.mu.OZ.AU (Christopher Boek)
Subject: Re: Cheesy convestibles???
Organization: Computer Science, University of Melbourne, Australia
Date: Tue, 22 Dec 1992 00:44:31 GMT

yahnke@macc.wisc.edu (Ross Yahnke) writes:

>In the Cheese Shop routine John Cleese talks about consuming "cheesy 
>convestibles"... What was the word he used? Was it "convestibles"?
>Does it mean food? I can't find it in the dictionaries I've looked in...

I believe it was 'comestibles'

>Thanks!
Anytime. *:)

Chris.

--
|  ||| |||  |  ||| ||| |||  |  ||Christopher Boek - boek@mullian.ee.mu.oz.au
|  ||| |||  |  ||| ||| |||  |  ||  Dept Elec Eng Univ of Melbourne Australia
|   |   |   |   |   |   |   |   | /  "Anybody remotely interesting is mad in
|___|___|___|___|___|___|___|___| \_/\_/\_/\_/\__/(:*-  some way or another"
Newsgroups: rec.puzzles.crosswords
From: ross@bryson.demon.co.uk (Ross Beresford)
Subject: Re: Computer Crosswords (was Re: COMPUTER JOURNAL ...)
Organization: Bryson Limited, Reading, UK
X-Newsreader: TIN [version 1.1 PL6]
Date: Tue, 22 Dec 92 19:35:41 GMT

Chris Long (clong@romulus.rutgers.edu) wrote:
: This is the easy part; the hard part is tagging all of the (thousands)
: of words, which must be done by hand.

In this regard, you may find the MRC2 database in the Oxford Text
Archive (anonymous ftp to 129.67.1.165) useful.

That database (originally derived from the Shorter Oxford) includes a
lot of specialised psycholinguistic information that I imagine you
could make good use of.

A start would be to base your score on one of the various written
frequency values, giving all the unrated words a low score.

: But
: assuming "fuzz" is in all the lists, it gets a great score between
: that and having the doubled "z".

For crosswords, this aspect of the scoring is the opposite from what
I'd expect. Both from the point of view of making filling the grid
easier, and of making clueing the words easier.

I would give preference to words putting high frequency letters at
the given positions in the unassigned crossing lights. One
problem with this is that you could end up putting the same high
(or low from your POV) scoring words in every grid.

: Finally, the hardest part doing the clues!  Anyone know how to
: automate these?  :)

Perhaps someone is doing this as their master's thesis right now?
IMHO it's an easier problem than parsing and interpreting clues
which is what Mr Hart seems to be trying to do.

Seriously, from my experience of compiling puzzles, the grid
construction stage is often slow and painstaking and well-suited
to some sort of automated help.

Grid construction may get easier with experience, but I think an
automatic means of filling in corners around thematic bits in
a grid would always save a substantial amount of time that could
be better spent thinking up imaginative themes and/or clues.

-- 
Ross Beresford
Email: ross@bryson.demon.co.uk           Voice: +44 734 344153
Bryson Limited, 10 Wagtail Close, Twyford, Reading, RG10 9ED, UK
Newsgroups: rec.puzzles
From: mag@cs.uiuc.edu (Tom Magliery)
Subject: Re: FAQ list
Reply-To: mag@cs.uiuc.edu
Organization: University of Illinois at Urbana-Champaign
Date: Sat, 2 Jan 1993 16:06:47 GMT

chris@questrel.com (Chris Cole) writes:

>The only thing I have to add to this is that one of the volunteers for
>maintaining the FAQ per se has been selected, and is now hard at work
>on the FAQ.  This should be posted shortly, and will be posted
>regularly.

As the designated volunteer, let me further add that I have just
returned from vacation myself, and, having too much time on my hands,
I shall be producing the first version of the FAQ very soon.

mag
-- 
Tom Magliery ** Dept of CS ** 1304 W Springfield ** Champaign IL 61820 ** USA
From: mouse@thunder.mcrcim.mcgill.edu (der Mouse)
Newsgroups: rec.puzzles
Subject: Re: The Rifleman Problem
Date: 22 Dec 92 18:51:33 GMT
Organization: McGill Research Centre for Intelligent Machines

In article <Dec18.162314.53024@yuma.ACNS.ColoState.EDU>, boll@CS.ColoState.EDU (dave boll) writes:
> In article <1992Dec18.033119.19454@thunder.mcrcim.mcgill.edu> mouse@thunder.mcrcim.mcgill.edu (der Mouse) writes:
>> In article <Dec15.235132.63842@yuma.ACNS.ColoState.EDU>, boll@CS.ColoState.EDU (dave boll) writes:
>>> N riflemen are situated randomly on a plane.
>> Um, this needs more precision.
> Well, I believe this caused some confusion during the Omni puzzle as
> well.  As I dimly recall, some people used a circle, some a square.
> I think the most 'elegant' solution is the surface of a sphere, as
> this eliminates boundary situations.

It also flies in the face of the problem statement!  "...on a plane"
does not, to me, seem to permit using a sphere.

Also, what about distance ties?  Or are they ignored as a set of
probability zero?

					der Mouse

			    mouse@larry.mcrcim.mcgill.edu
Newsgroups: rec.puzzles
From: zhang@climat.geology.yale.edu
Subject: Re: simple number puzzle
Organization: Yale University GFD Computing
Date: 22 Dec 92 03:57:26 EDT

In article <1992Dec22.010621.19817@dartvax.dartmouth.edu>, J.Theodore.Schuerzinger@dartmouth.edu (J. Theodore Schuerzinger) writes:
> Yuzuru Hiraga writes:
> 
> A simple number puzzle for Christmas...
> # sorry if this is in the FAQ: ours just expired.
> 
> What positive integer cannot be expressed as a sum of 2 or more
> consecutive integers?
> 
> I believe the answer is 2^n power (where n is an integer) can't be
> expressed as the sum of consecutive integers, but all other numbers
> can.
> 
> **End of quoted material.
> 
> Proof:
> 
> 1. All odd integers can be expressed as the sum of two consecutive
> integers.
> 
> 2. 4 consecutive integers will give all numbers with exactly one factor
> of 2.
> 
> 3. x number of consecutive integers, where x is prime (and not equal to
> 2), will give you all multiples of x (starting at x^2+x/2).
> 
> Numbers lower than (x^2+x)/2 fall into two cases:
> a) Odd numbers, covered above.
> b) Even numbers.  As these have only one multiple of 2, they will
> obviously be a number that has a remainder of 2 when divided by 4 (ie.
> case #2 above).
> 
> This solves all numbers except for those whose only factors are 2 (ie.
> powers of 2).
> 
> As I am leaving to go home for Christmas tomorrow morning, anyone who
> has the rest of the proof should email me directly with it.
> 
> Thanks!
> 
> --Ted Schuerzinger
> email: .zed@Dartmouth.EDU
> "I should have known it would be bad vodka when all the label said was
> 'Russian Vodka'."
Newsgroups: rec.puzzles
From: kanad@quip.eecs.umich.edu (Kanad Chakraborty)
Subject: Re: new year's problem
Organization: University of Michigan EECS Dept., Ann Arbor
Distribution: rec
Date: Sat, 2 Jan 1993 16:09:12 GMT

In article <1993Jan2.1584.7529@channel1> "eliot gelwan" <eliot.gelwan@channel1.com> writes:
>On 12-31-92 KEITH F. LYNCH  wrote:
>
>KFWhat property did 1987 have, that no year after it will have
>KFuntil 2013?
>
>Prime numbers
>

Or, no repeated digits.

>KFWhat property did 1961 have, that no year
>after it will have until 6009?
>
>turn 'em upside down and see.
>
>                   |
>...eliot          -*-              Postlink: ->CHANNEL1 [R/O okay]
>                   |               Internet: eliot.gelwan@channel1.com
>
>---
>              [in Brookline MA 11:47 pm, Friday 01/01/93]
>--
>Channel 1 (R)   Cambridge, MA
>

Kanad
Newsgroups: rec.puzzles
From: nittab@aix02.ecs.rpi.edu (Bhima Nitta)
Subject: Re: Lost Solution
Organization: Rensselaer Polytechnic Institute, Troy NY
Date: Thu, 24 Dec 1992 19:13:44 GMT

Newsgroups: rec.puzzles
Subject: Re: Lost solution
Summary: 
Expires: 
Followup-To: 
Distribution: 
Organization: Rensselaer Polytechnic Institute, Troy, NY
Keywords: 

In article <rbarnick-241292103910@cosadpm12.mitre.org> rbarnick@mitre.org (Barnie Barnick) writes:
>*****
>Tim,
>The answer is 4 and 19.  
>*****


Now my interest is piqued. Why is this the solution ?

Yours ignorantly,

Bhima





>
>In article <1992Dec22.193053.24084@bernina.ethz.ch>, timh@igc.ethz.ch (Tim
>Harvey) wrote:
>> 
>> Dear Netters,
>> 	A log while ago I collected the following brainteaser;
>> 
>> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>> 
>> 
>> Mr. S. and Mr. P. are both perfect logicians, being able to correctly deduce


Newsgroups: rec.puzzles
From: arromdee@godel.cs.jhu.edu (Ken Arromdee)
Subject: Re: Direction of the sun
Organization: Johns Hopkins University CS Dept.
Date: Thu, 24 Dec 1992 09:01:23 GMT

In article <Bzr9GF.3uM@hplabs.hpl.hp.com> potamian@hpl.hp.com (Spyros Potamianos) writes:
>However a friend of mine pointed out that both systems must give the same
>answer, as this is a "kinematic" problem (is this the correct term???) and no
>forces are involved, so both a geocentric and a "solarcentric" point of view
>must provide the same answers.

In the original geocentric and heliocentric systems, light rays move in
straight lines.  In the mapped-geocentric-onto-heliocentric and vice-versa,
light does not move in straight lines.  There is therefore no reason to
expect the same answer in X and Y-mapped-onto-X systems.

Your calculations show that in Y and in Y-mapped-onto-X systems you get the
same answer, but the latter does not give the same answer as X.
--
"the bogosity in a field equals the bogosity imported from related areas, plus
the bogosity generated internally, minus the bogosity expelled or otherwise
disposed of."  -- K. Eric Drexler

Ken Arromdee (arromdee@jyusenkyou.cs.jhu.edu, arromdee@jhunix.hcf.jhu.edu)