HDTenEightyP/NetNews huggingface dataset:
From: ghorne@fox.nstn.ns.ca (Garth Horne)
Subject: references or articles on geoboards / geoblocks
Keywords: geoboards geoblocks
Organization: Environment Canada
Date: Tue, 26 Jan 1993 00:28:30 GMT

I am a teacher seeking information, leads or articles concerning '
geoboards or geoblocks'. Can anyone is this mail group assist. Thanks for 
your time. 
Newsgroups: sci.math
From: dpb@a.cs.okstate.edu (D. Paul Benjamin)
Subject: category theory question
Organization: Oklahoma State University, Computer Science, Stillwater
Date: Mon, 25 Jan 93 20:13:10 GMT

Does the forgetful functor from groups to semigroups have
a left adjoint?

Thanks in advance.

Paul Benjamin

Newsgroups: sci.math
From: rivin@SAIL.Stanford.EDU (Igor Rivin)
Subject: Re: Which CAS have BA's in math?
Organization: Computer Science Department,  Stanford University.
Date: Fri, 22 Jan 1993 22:05:32 GMT

In article <106190@netnews.upenn.edu> weemba@sagi.wistar.upenn.edu (Matthew P Wiener) writes:
>In article <1993Jan19.205434.10234@leland.Stanford.EDU>, ilan@leland (ilan vardi) writes:
>>>I doubt there is a computer algebra system that can get a degree
>>>in mathematics: they don't write proofs (yet).  However, I tried the
>
>>They write papers though. Shalosh B. Ekhad, Doron's Zeilberger's computer,
>>has written a number of papers (more than I have, I think).
>
>What is the story about SBE?  The papers I've seen seem to be somewhat
>demented in enthusiasm, a feeling reinforced by the phoney name, which
>gives the impression (being Hebrew for 3-in-1) that the author himself
>is a demented with enthusiasm member of the Jews for Jesus.
>-- 

The story is that the name is not any product of the Illuminati
conspiracy, nor of the Jews for Jesus. The computer in question is an
AT&T 3B1 model Unix PC. You figure it out. The enthusiasm is perfectly
understandable -- if you were a computer proving identities, you would
be enthusiastic too. On the other hand, suspecting that a computer is
a member of Jews for Jesus (or demented, for that matter), is carrying
anthropomorphism a bit far, don't you think? If, on the other hand,
you comments were directed at Doron Zeilberber (one of the least
demented mathematicians of my acquiantance), I view them as slanderous
and in extremely bad taste, especially as they are obviously made
behind the back of their subject.
From: eli@cisco.com (Steve Elias)
Newsgroups: sci.math
Subject: "new calculus theorem" found by 19 year old Miami student?
Date: 27 Jan 93 11:12:00
Organization: cisco Systems
NNTP-Posting-Host: glare.cisco.com
In-reply-to: gore@inferno.rutgers.edu's message of 25 Jan 93 03:14:32 GMT


did anyone else see the wire story about a freshmen at
a Miami school -- she discovered some new theorem.
i am wondering what exactly the theorem is...  clues, anyone?

/eli
Newsgroups: sci.math
From: gm115@emu.pmms.cam.ac.uk (Gabor Megyesi)
Subject: Re: Combinatorial Problems
Organization: DPMMS University of Cambridge
Date: Sat, 23 Jan 1993 12:18:00 GMT

In article <93022.114846DCC117@psuvm.psu.edu> <DCC117@psuvm.psu.edu> writes:
>   Has anybody worked with, or know the solution to, the
>following problem ?
>
>   A 6-by-6 chessboard is perfectly covered with 18 dominoes.
> Prove that it is possible to cut it either horizontally or
> vertically into two non-empty pieces without cutting through
> a domino, that is, prove there must be a fault-line.
>

There are 10 lines and 18 dominoes. For parity reasons any line must cut
through an even number of dominoes, so if a line cuts through a domino, it
must cut through at least 2. Therefore the 18 dominoes cannot cover all 10
linmes, so there must be a fault-line. Q.E.D.

Gbor Megyesi
G.Megyesi@pmms.cam.ac.uk
Newsgroups: sci.math
From: bs@gauss.mitre.org (Robert D. Silverman)
Subject: Re: Distribution of primes mod 4
Organization: Research Computer Facility, MITRE Corporation, Bedford, MA
Date: Fri, 22 Jan 1993 00:46:04 GMT

In article <1993Jan21.212120.251@leland.Stanford.EDU> ilan@leland.Stanford.EDU (ilan vardi) writes:
:In article <1993Jan21.141800.17997@linus.mitre.org> bs@gauss.mitre.org (Robert D. Silverman) writes:
:>
:>let u(x) = #{n <= x;  pi(n,1,4) < pi(n,3,4)}
:>
:>Then one would expect that u(x) = x/2 for almost all x. That is to say,
:>for large x, about 1/2 the integers less than x have pi(n,1,4) < pi(n,3,4)
:>and for about 1/2 the integers the inequality is reversed. This can be
:>made more precise;
:>
:>u(x) = x/2 + O(x^{1-epsilon})  for any fixed epsilon.
:
:
:Yo! This is clearly wrong, and you can't do better than epsilon = 1/2
:(which is the generalized Riemann Hypothesis). In other words 
:epsilon <= 1/2 in the above term. 

Yes. I was too hasty. I should have said any fixed epsilon near 0,
or as you say less than 1/2.


--
Bob Silverman
These are my opinions and not MITRE's.
Mitre Corporation, Bedford, MA 01730
"You can lead a horse's ass to knowledge, but you can't make him think"
From: heading@ccint1.rsre.mod.uk (Anthony J.R. Heading)
Newsgroups: sci.math
Subject: Re: request for info on game theory
Date: 27 Jan 93 18:02:02 GMT
Organization: Defence Research Agency
NNTP-Posting-Host: amigos.dra.hmg.gb

davidd writes
> 
> Hello, I'm a new reader to this news group and was wondering if
> anyone could offer any advice. For some years now I've had
> various ideas for a computer/board game. In a nutshell, (in the
> computer version) you would play against a autonomous agent. (no,
> not a shoot them up thing) Anyway I was talking to a friend over
> lunch the other day and was babbling incoherently about some of
> my ideas and she was wondering what game theory books I had
> studied or used. I hadn't. I didn't really know anything about game  
theory
> as such so I thought I'd better look into it. If anyone could
> offer any recommondations, I'd appreciate it. Hmmm, just a
> thought, perhaps should I be looking for any relevent AI
> book...??? Thanks for your time and help.

I'd recommend reading Hofstader's (?spelling) book
"Metamagical Themas" - it gives rather a good overview of his
thought processes in going through trying to do what you want
to do, and explains concisely the strengths and weaknesses of
game theory. As well as lots of other funky stuff.

On a more conventional academic level, the definitive book
is Von Neumann and Morganstern's "Theory of Games". In it they
invent game theory. So it'll tell you all you need to know, but
you have the tedium of working out the weaknesses for yourself.

Effectively, in a sentence, game theory is about going 'all out'
for a draw. You assume your opponent is going to play optimally,
and play to block him as best you can. Your move is to minimise
the opponents maximum gain. In a symmetric game, this tends to
lead to a draws - however clever you are, a game-theory based
opponent will block you: not try to win, simply try not to lose.
It'll have considered every move you could make, and play to
make sure that none of them are a real winner for you.

OK, this is fairly good - but it wouldn't work very well if your
opponent is a bit predictable. If you can model your opponent -
read his hand as it were - and bluff a bit, you stand a chance
of beating him. This is a consequence of the way people play games.
A game-theoretic opponent is unreadable - completely random within
its prescribed strategy. In fact, while it's normally an advantage
to know your opponents strategy - with a game-theory based opponent
the strategy can be laid open and bare, and it just doesn't help.

Anthony
Newsgroups: sci.math
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: Mackey-Glass solutions
Organization: Department of Chemistry, University of Toronto
Date: Mon, 25 Jan 1993 23:43:53 GMT

In article <1993Jan25.171732.4712@iplmail.orl.mmc.com>
markb@iplmail.orl.mmc.com (Mark Bower) writes:
>I am looking for papers describing solution techniques and giving
>a closed form solution of the Mackey-Glass equation:
>
>dx                 x(t - T)
>--  = -b x(t) + a ----------   10
>dt                1 + x(t - T)^

     An equation of this sort is known as a delay-differential equation.
Here are a few papers that discuss numerical solutions of delay-differential
equations:

George Marsaglia, Arif Zaman and John C.W. Marsaglia, Math. Comp. 53, 191-201
      (1989).  This paper describes a very elegant method of solution
      based on power series expansions between the knots.
G.S. Virk, IEE Proc. D 132, 119-123 (1985).  This paper extends
    Runge-Kutta methods to delay-differential equations.  The method
    presented is probably a reasonable compromise between computational
    efficiency and code complexity.
Irving R. Epstein and Yin Luo, J. Chem. Phys. 95, 244-254 (1991).  In
      addition to the application of delay-differential equations to
      kinetics, several simple numerical integration methods are
      presented.

     				Good luck.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca
Newsgroups: sci.math
From: syliao@rice-chex.ai.mit.edu (Stan Y Liao)
Newsgroups: sci.math
Subject: Re: why is pi irrational
Date: 21 Jan 1993 18:23:21 GMT
Organization: MIT Artificial Intelligence Laboratory
NNTP-Posting-Host: rice-chex.ai.mit.edu

> When it says the Earth is flat, however, it is inaccurate, rather than
> imprecise.

It must be kept in mind, however, that for an ancient people the Earth
DID look flat.  They did not have enough instruments to observe beyond
the extent they could.  For all practical purposes of the ancient life
the Earth is flat.  You may as well say, in anticipation of the
progress in science, that our current understanding of the universe is
(or will be) inaccuarate.  For in ten or twenty years, we will
certainly be able to observe more than we can now.




---------------------------------------------------------------------------
Stan Yi-Huang Liao                                  syliao@rle-vlsi.mit.edu
---------------------------------------------------------------------------
Research Laboratory of Electronics    Massachusetts Institute of Technology
Newsgroups: sci.math.symbolic
Date: Thu, 21 Jan 1993 13:14:22 -0500 
From: Richard Dale Romero <rickr+@CMU.EDU>
Subject: Re: Help finding Equation editor?
Distribution: na

Excerpts from netnews.sci.math.symbolic: 19-Jan-93 Help finding Equation
editor? ACPS7221@RyeVm.Ryerson.C (653)


>   I'm sorry if this is not the appropriate newsgroup, but I have tried several
> others without a response.  I am looking for a WYSIWYG type program that I can
> run in the X11 environment, that would allow me to make mathematical equations,
> and save in any popular graphics format. (postscript, tiff, bitmap, etc).

Always liked FrameMaker myself.

-rick romero
From: rgonzal@gandalf.rutgers.edu (Ralph Gonzalez)
Newsgroups: sci.math.symbolic
Subject: Macintosh symbolic software recommendations?
Keywords: macintosh
Date: 26 Jan 93 17:28:15 GMT
Organization: Rutgers Univ., New Brunswick, N.J.


Someone recently posted a similar question, but my mail to him
bounced...

Can someone recommend or summarize inexpensive symbolic math
software for Macs? I understand MathCad does some symbolic
stuff and can be had for $79... How about student versions of
Mathematica or Theorist?

Thanks. I'll summarize emailed responses.

-Ralph Gonzalez
-- 
Ralph Gonzalez, Computer Science, Rutgers Univ., Camden, NJ
Phone: (609) 225-6122; Internet: rgonzal@elbereth.rutgers.edu
--
Newsgroups: sci.math.symbolic
From: edp@math.zk3.dec.com (Eric Postpischil)
Subject: Re: What about MathCad...?
Reply-To: edp@math.zk3.dec.com (Eric Postpischil)
Organization: Digital Equipment Corporation
Date: Thu, 21 Jan 1993 14:28:27 GMT

In PC Magazine (one of the January issues, in which they reviewed video
boards), there was an ad with a coupon for a free "MathCAD Working
Model" which the text said included a demonstration and a fully
functional version of MathCAD.  I don't understand what the catch is,
but I've sent for it.  I suggest anybody interested in MathCAD look for
PC Magazine in a library.


                                -- edp (Eric Postpischil)
                                "Always mount a scratch monkey."
                                edp@rusure.enet.dec.com
Newsgroups: sci.math.symbolic
From: bastiaanssen@rullf2.leidenuniv.nl
Subject: inequalities in mma ???
Organization: Leiden University, Medical Informatics
Date: 22 Jan 93 09:23:20 +0100

Hello,

Can anyone help me solving inequalities in Mathematica?
For example, how do I check:
(x+2 < 5) == (x<3)	  ?
Do I have to implement rules for substracting the same
term at each side of the inequality sign? Is there a toolbox
for symbolic manipulation within inequalities? Are there
text books or papers avaible about this subject?
All information is welcome!

Best regards,

Erica Bastiaanssen
Medical Informatics, University of Leiden, The Netherlands
e-mail: "BASTIAANSSEN@RULLF2.LeidenUniv.nl"
From: frick@aristoteles.ira.uka.de (Arne Frick UniKa)
Newsgroups: sci.math.symbolic
Subject: Q: Constructing Voronoi diagrams in Maple
Date: 27 Jan 1993 09:30:50 GMT
Organization: Universitaet Karlsruhe
Distribution: world
Reply-To: frick@ira.uka.de
NNTP-Posting-Host: i44s2.ira.uka.de
Keywords: Maple V, Voronoi diagrams

In our algorithms class we are teaching methods from algorithmic geometry. Therefore,
we would like to be able to have some slides showing Voronoi diagrams and their
construction.

Due to the fact that construction by hand is somewhat tedious, I wonder whether there is
a Maple program for constructing (and drawing) Voronoi diagrams.  

This should certainly be possible given the graphics capabilities of Maple.

Any pointers welcome.
-- 
Arne Frick		phone: 0721/608-4762	fax: 0721/6622-968
Universitaet Karlsruhe		email: frick@ira.uka.de
Postfach 6980, 			       frick@karlsruhe.gmd.de
Vincenz-Priessnitz-Str. 1, W-7500 Karlsruhe 1, GERMANY	        
Newsgroups: sci.math.symbolic
From: harman@helios.usq.EDU.AU (christopher harman)
Subject: Mathematica Microsoft Windows Graphics Text Fonts
Summary: Enlarging graphics text fonts Mma Microsoft Windows
Keywords: Mathematica,Postscript,Microsoft-Windows,Graphics-Text-Fonts
Organization: University of Southern Queensland
Date: Thu, 28 Jan 1993 06:19:11 GMT


I am having trouble printing scaled text-fonts in graphics mode
using Mathematica under Microsoft-Windows.
Under DOS I could do it using Display[] to create the postscript file
and then using the program hardcopy to create an encapsulated postscript
file which can then be suitably edited for a postscript printer.
But under Windows I cant see any way of doing this. All I want to be able to
do is to be able to label my diagrams with text in the size of my choosing.
Any help will be much appreciated.
Chris Harman,Univ of Southern Queensland 

Newsgroups: sci.math.symbolic
From: physcaw@cwis.unomaha.edu (Glenn Sowell)
Subject: Summer Workshop Announcement
Summary: An NSF summer workshop on computer algebra in physics education
Keywords: Physics, Computer Algebra
Organization: University of Nebraska at Omaha
Date: Tue, 26 Jan 1993 16:02:26 GMT


                       Using Computer Algebra Software 
                        To Teach Undergraduate Physics
 
                      A Leadership Development Workshop
                   at the United States Air Force Academy
                           Colorado Springs, CO
          
                             July 11-23, 1993


Computer algebra software can symbolically solve equations, integrate, 
differentiate, solve differential equations, manipulate matrices and much more. 
Its incorporation into the physics classroom is only just beginning. This 
workshop will provide participants an opportunity to master a computer 
algebra program and develop strategies for its integration into the 
undergraduate physics curriculum. Workshop participants will then be able to 
lead workshops of their own in local and regional settings.

Four powerful computer algebra packages will be available at the workshop:
      Derive
      Maple
      Mathematica
      Theorist

Workshop participants may work on either Apple Macintoshes or PC's (DOS or 
Windows). Participants must be college faculty involved in undergraduate 
physics programs.

      The workshop will provide expenses and a stipend for all participants.

      The application deadline is March 5, 1993.

The workshop faculty:

      Glenn Sowell
      University of Nebraska at Omaha
      Marvin De Jong
      College of the Ozarks
      Patrick Tam
      Humboldt State University  

This workshop is sponsored under a National Science Foundation faculty 
enhancement grant #USE-9255505

If you would like more details and an application, please send the following 
information by mail, fax or e-mail to the appropriate address below:

Name__________________________________________________  
Institution_____________________________
Address_________________________________________________________________
City, State, Zip________________________________________.      
      
      Mail to:    Glenn Sowell
                  Department of Physics
                  University of Nebraska at Omaha
                  Omaha, NE 68182-0266
      Fax:        (402) 554 - 3100
      email:      physcaw@unomaha.edu
Newsgroups: sci.math.symbolic
From: aardvark.ucs.uoknor.edu (K K Spriestersbach)
Subject: Re: Where to obtain Signal Proc. Pack.
Originator: news@essex.ecn.uoknor.edu
Date: Wed, 27 Jan 1993 15:54:37 GMT
Organization: Univ. of Okla., Univ. Comp. Serv./AUS
Followup-To: sci.math.symbolic

Mathematica has an e-mail server which I find helpful. The address is
MathSource@wri.com . A large package titled "Signal Processing Packages
and Notebooks" can be obtained by sending the message "Send 0202-240". 
A small package titled "Digital Signal Processing" can by obtained by
sending
the message "Send 0200-327". For a complete index send a message on two
lines :
MaxFull 1000
Find * .
Hope this helps.
Newsgroups: sci.math.symbolic
From: harris@max.physics.sunysb.edu (Brian Harris)
Subject: Re: help ; High Energy Physics & Maple
Organization: Institute for the Theoretical Physics
Date: Mon, 25 Jan 1993 17:57:09 GMT

There is a Maple package called HIP by Eran Yehudai who is now at Fermi Lab 
which I think does what you want.  It is a package for symbolic calculation 
of Feynman diagrams and relativistic kinematics.  You can get the package 
from ftp.uu.net in the directory pub/physics/maple.  There is also another 
version of HIP for Mma at mathsource.wri.com.  Good luck.


Brian Harris
From: zou@ccs.northeastern.edu (Chendong Zou)
Newsgroups: sci.math.symbolic
Subject: help needed
Date: 28 Jan 93 00:04:36 GMT
Organization: College of CS, Northeastern U

Hi:

Does anyone know if there is a  answer book for exercises in 
John E. Hopcroft, J.D. Ullman's classic book "Introduction
to Automata theory, Languages, and Computation" ? 

Please email me if you know. Thanks.

-zou
Newsgroups: sci.math.symbolic
From: schoen@ghost.dsi.unimi.it
Subject: Is Wolfram Res. still alive???
Organization: Computer Science Dep. - Milan University
Date: Tue, 26 Jan 1993 08:55:32 GMT

In the last few months I sent three e-mail messages to register@wri.com,
as well as a fax with my registration form of the (BUGGY) Mathematica v
2.0.4 and an order form for v. 2.1 for Windows.

Never got any answer!

Do you know what happened to Wolfram Research??

Maybe they are out of e-mail and fax, or simply they disregard
customers?

-- 
| Fabio Schoen (assoc .prof. of Op.Res.)        e-mail:                     |
| Dipartimento di Scienze della Informazione    schoen@ghost.dsi.unimi.it   |
| via Comelico 39/41 - I20135 Milano ITALY                                  |
| fax: +39 (2) 55006.276 or 373                 Tel: +39 (2) 55006.319      |
From: dlj0@ns1.cc.lehigh.edu (DAVID L. JOHNSON)
Newsgroups: sci.math.symbolic
Subject: Re: What about MathCad...?
Date: 21 Jan 93 20:23:17 GMT
Organization: Lehigh University

In article <9610001@hpfcso.FC.HP.COM>, wayne@hpfcso.FC.HP.COM (Wayne Covington) writes:
>
>The advertisement with the $79 offer tells a person very little about what
>it can and cannot do.  So I visited some computer bookstores yesterday in
>hopes of learning more, but none of them had any books on MathCad.  Nor do I
>recall many MathCad postings in this group, even after Frank posted his
>inquiry.  If they are on version 3.1, it must have been around long enough
>to acquire a following.  Perhaps MathCad is shunned because its capabilities
>fall short of those of Maple, Mathematica, and other commonly mentioned
>computer algebra systems?
>
In my opinion, anyone who has used a real CAS will quickly get frustrated
with MathCad.  It is not easy to generate graphics (I'm sure to get a lot
of responses on this that say:  all you have to do is this...and this...and...
but I only got poor plots out of it after trying several times.  And surfaces
are nearly impossible), it doesn't want you to define variables - only letters
that are attached to fixed numbers.  That may be useful to some, but it is not
really computer-algebra.

Those who use it tend to mention that the matrices are easier to enter than in
Maple or Mma.  That is true - but again, I don't think it'd handle variable
entries easily.  It is not extensible, not flexible.

Even for typesetting, it does things its' way, not yours.  Better to paste
your TexForm output into a TeX document.
>Wayne
>
-- 
Sincerely,

David L. Johnson                    ID:  dlj0@lehigh.edu
Christmas-Saucon Hall #14, rm 241        dlj0@chern.math.lehigh.edu
Department of Mathematics

Lehigh University                   Telephone: 215-758-3759 (office)
Newsgroups: sci.math.symbolic
Subject: Re: unexpected result
From: a_rubin@dsg4.dse.beckman.com (Arthur Rubin)
Date: 27 Jan 93 23:04:22 GMT
Distribution: usa
Organization: Beckman Instruments, Inc.
Keywords: roots mma

In <rvk.728154627@wink> rvk@blink.att.com (Bob Kline) writes:


>	Running mma 2.1 on a Sparc-2, I input the following:

>	Solve[{Sqrt[x]+y==11,x+Sqrt[y]==7},{x,y}].



>	this results in four roots.  substituting the result in
>	Sqrt[x]+y (or Sqrt[y]+x), only two of the roots are
>	correct.  the other two are numbers like 14.nnn and 17.nnn.


Try setting the option VerifySolutions-> True.

By default, mma solves the equations:

{u^2 ==x,u+y==11,v^2==y,x+v==7}

and eliminates u and v.  For the remaining solutions, u and/or v is
negative.
--
Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal)
My opinions are my own, and do not represent those of my employer.
My interaction with our news system is unstable; please mail anything important.
Newsgroups: sci.math.symbolic