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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

100.0. "6-month index" by HARE::STAN () Fri Jul 27 1984 01:33

In the first response to this note, you will find the 6-month index
to this note file, covering the period 20-Jan-1984 through 26-Jul-1984
(the first 100 notes).

Following that you will find additional comments by your moderator.
T.RTitleUserPersonal
Name
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100.1HARE::STANFri Jul 27 1984 02:52207
	Index to MATH.NOT	27-Jul-1984	(notes 1-100)

		References to a main note (of the form x.0)
		mean that the topic is discussed throughout
		that note;   so when investigating it,  you
		should peruse the responses to that note as
		well.   This index was produced by hand.  A
		complete concordance can  be found in  file
		HARE::SYS$NOTES:MATH.CRD.

Topic				References
-----				----------
120 degrees			22.0
1983				24.0
1984				24.0
3 inverters from 2		68.0
7-section			17.0
A/P				31.0
Absolute difference triangles	42.0
AI programs			20.2
algorithm design conference	82.0
algorithm for division		87.0
algorithm for reciprocal	87.0
alphametic solver		45.0
alphametics			45.0, 46.0
AMSTeX				43.0
approximations			56.0
Arnold Arnold			16.3
ASIN				27.0
backup datatypes		96.0
BCAL				15.0
Beyond Floating Point		23.0
Brent multiprecision package	26.0
British soldiers problem	69.0
bugs				89.0
calculus			34.0
CALX				15.0
casting out 9's			56.1
chain problem			40.0
chess problems			33.0
Clifford's theorem		20.3
coin problems			7.0, 55.0
Combinatorial Algorithms	5.0
complex log			32.6
complex polynomial		48.1
continued fractions		47.3, 57.4, 61.0, 98.0
convergent sequence		48.0
Conway, J. H.			10.0
counterfeit coins		55.0
curve fitting			85.0
curve in square			31.0
curve through 3 points		85.0
data analysis program		77.0
dice problems			97.0
difference equations		61.0
difference triangles, absolute	42.0
Difference triangles, distinct	14.0
differential equations		61.2
Digicalc			14.4
digital filters			36.0
disection puzzles		83.0, 84.0
Distinct Difference Triangle	14.0
doubly-true alphametics		46.0
duality				90.0
e, calculation of		92.24
equations from digits		24.0
error-correcting codes		6.1, 6.2
factorials			50.0
factoring			19.0, 21.0, 30.0, 49.0, 51.0
factoring programs		73.0, 81.0
factoring, algebraic		72.0, 94.0, 99.0
Fermat prime			17.1, 17.4
Fermat's Last Theorem		16.0
Fibonacci numbers		59.0
Fibonacci polynomials		94.0
firing squad synchronization	69.0
floating point			38.0
floating point package		47.0
foreign numbers			44.0
four fours problem		24.5
Frame formula			56.2, 56.4
generating functions		61.2
geometric duality		90.0
GOTO-less programming		5.1
graph theory			53.0
Guess a number			6.0
Hamming code			6.3, 6.5
handshaking			18.0
harmonic series			52.0
Heronian triangles		70.0
horizon calculation		56.3
IEEE floating point standard	38.0
IEEE library			36.0
IMSL				60.0, 74.0
index				100.1
integer sequences		93.0
integrals			25.0, 86.0
interest calculations		56.0
inverters problem		68.0
IXP				28.0
i^i				32.0
job scheduling			75.6
Johnson's algorithm		58.3
Joy of TeX			43.0
k-subset			5.0
lattice points			22.0, 31.6
league scheduling		75.0
LINPAK				60.0
LISP				57.5
LN01				13.1
MACSYMA				15.0
MASS-11				15.0
math package			60.0
Merten's conjecture		39.0
microvaxen			96.0
modulo problem			66.0
Morley's theorem		20.3
most wanted factorizations	51.6
MP				26.0, 92.17
MPSET				26.2
multiprecision package		28.0
muMATH				15.0
N-clusters			41.0
NAG				60.0
non-procedural programming	8.4
NSA				16.6
number systems			23.0
palindromic sequences		95.0
Partitions			5.0
Partitions, balanced		9.0
Pell equation			57.0
Permanent			5.0
Permutations			5.0, 58.0, 66.5
pi, 10000 digits		92.8
pi, approximation		37.0
pi, calculation of		92.0
PICOMATH			15.0
Pizza				17.0
platonic solids			90.0
point symmetric graphs		53.0
Pollard's rho method		81.6
polytopes			90.1
powers				29.0
powers mod M			66.0
pretty theorems			20.0
prime plus power of 2		64.0
Prime producers			10.0
Primes, 333...3			21.0
Primes, A.P.			4.0
primes, alleged generation of	16.0
Primes, Mersenne		2.0, 51.0
primes, probable		21.1
probability, conditional	63.0
Quacks				16.2
queens, non-attacking		33.0
radix representation		67.6
Ramsey theory			54.0
random numbers			81.5
random variables		63.1
reciprocals, algorithm for	87.0
recurrences			61.1
recursion for sqrt 2		67.0
repunits			49.0
rifles				69.0
right triangles, solving	56.2, 56.4
RISK				97.3
Roman numerals			12.0
round robin schedule		75.5
RTL math LIBRARY		96.0
RTL math manual			80.0, 88.0
Rules				1.0
SAC-2				15.0
Scales, spring			7.0
scheduling			75.0
seminars			23.0, 35.0
semiregular polyhedra		91.0
SLATEC				60.1
SMP				15.0
SNOBOL4				12.0
spheres, opposite of		62.0
Spherical Trigonometry		11.0
sqrt 2				67.0
squaring makes smaller		79.0
STAT				77.0
STR$DIVIDE			89.0
sum of squares			78.0
Summation			59.0
Symbolic Math			15.0
system III			74.0
tangents to two circles		65.0
TECO macros			92.1
temperature conversion		56.0
test data			81.0
Tetrahedron			11.0
TeX				13.0, 43.0
TexBooks			13.2
three-body problem		16.1
TK!Solver			15.0
Tower of Hanoi			8.0
trigonometric identities	71.0
trigonometric sums		59.0
USENET				76.0
VAXIMA				15.0
Welcome				1.0
what are the 2 numbers		78.0
x^2+y^2+z^2			72.0
Zeta function			3.0
100.2HARE::STANFri Jul 27 1984 03:39102
		Open Problems		[comments by S. Rabinowitz]
		---- --------

As of 26-Jul-1984, the following problems are still open:

Note #	    description and comments
------      ------------------------
7.	spring scale coin problem.

	Solution will be published in the Monthly before long.

14.	Distinct Difference triangles.

	Not likely to be solved. Has been published in the James
	Cook Mathematical Notes. We'll see if they have any luck with it.
	Can some upper bounds be found? Peter and I have some upper
	bounds; but the details are embedded in the code and scribbled
	on a listing sitting in my office.

18.	Handshaking problem.

	Come on guys... This is an easy one.

22.	120 degree angle in 3D lattice.

	Let's hit this with some compute power!

33.	Combinatorial chess problems.

	Not likely to be solved soon.

41.	N-clusters problem.

	I was at one of the New York geometry seminars. Paul Erdos was
	speaking on unsolved problems in combinatorial geometry. He mentioned
	this as a long unsolved problem.  If Erdos can't solve it, I would
	forget about it.

42.	Absolute difference triangles.

	Appears hard.  Perhaps some more data would help.

53.	Point symmetric graphs.

	Jerry tells me this one stumped all the graph theory professors
	at Yale.

61.	Difference Equation.

	I've solved the differential equation (by hand) but have been too
	lazy to enter the computation.  Anyhow, this was of no use
	because the resulting function had an essential singularity at 0,
	so I was unable to recover the Taylor series.

	Sloane gives a reference to this sequence; but the reference
	(EUREKA - The Journal of the Archimedean Society) is to an
	obscure British journal that I can't find in any American libraries.
	Can any readers locate this journal in their library?

66.	Powers mod M.

	Let's keep working on this one...

67.	Recursion for sqrt(2)

	Several people are still actively working on this, but I think
	it's futile.

68.	n inverters from 2

	Peter and I have been discussing this privately, and have concluded
	that you can invert 4 signals with 2 inverters using a circuit that
	glitches.  The original proposal allowed glitches.  We have no
	formal proof yet that you can invert n signals with 2 inverters.
	There are feedback problems.  How about someone with access to
	a schematics editor and a circuit simulator to "build" the circuit
	for us and simulate it to see if it works or not, for n=5?

70.	Heronian triangles with one side twice another.

	Let's use up some computes!

72.	Factoring x^2+y^2+z^2

	Leroy Meyers sent me a simple proof these couldn't be factored.
	You should be able to prove it too.

83,84.	Lynn's dissection problems.

	I don't believe we have a definitive answer yet. Perhaps we never
	will.  Can anyone do better than the dissection we currently have?

94.	Factoring Fibonacci Polynomials.

	I recently learned that a change of variables will turn the
	Fibonacci polynomials into the Chebyshev polynomials (of the second
	kind) and I think lots is known about factoring Chebyshev
	polynomials; but I'm still researching this.

95.	Palindromic sequences.

	Anyone care to generate more data?
100.3HARE::STANFri Jul 27 1984 04:0133
	General Comments from your Moderator

Well, I'm very pleased.  This has been a very fun 6 months.
There have been a lot more contributions than I had expected
and they have all been of high caliber!

But there must be more mathematicians at DEC!  The author index
in the concordance shows only 28 contributors.  Please tell all
your mathematician friends about this file.  And if you read this
file but don't contribute: please don't be bashful.  So even if
you make a mistake once in a while; no one will blame you. The
whole purpose of this file is to keep us from stagnating and
forgetting all the mathematics that we may have once known. Math
can be lots of fun and computers can be used for recreational
mathematics as well as for systems programming. No item is too small.

Also, I'd like to see more contributions concerning mathematics
at DEC.  There must be R&D groups doing some interesting mathematics.
And I \know/ we have math routine libraries on each of our
operating systems.  Someone must be maintaining them...
So, if you're doing some mathematics for DEC, how about giving us
a short summary of what you're doing?  Maybe someone else can help
you.  Let's hear about the cryptography work that's going on;
and I know that there are guys doing error correction algorithms
out there in Colorado Springs for our smart disk controllers.
And schematic layout is clearly a problem in graph theory. etc.

Let me also thank everyone for the lack of chit-chat such as goes
on in most other notes files.  After reading SOAPBOX or TRIVIA,
it is a pleasure to read through this file.  And I can't get over the
fact that you mathematicians know how to spell!

			- Stanley Rabinowitz -