Mathematics

Largest Primes

Admin — Sun, 06 Apr 2008 15:19:49 GMT

Anyone heard of GIMPS, the Great Mersenne Prime Search? Since the creation of RSA Encryption, everyone is interested in Primes. There is a prize for the first person to find a 10 million digit primes. The record so far was 2^(32582657)-1, 9808358 digits in 2006. You can download their software to your computer as part of a distributed computing project, the program runs when your not using your computer to calculate new primes, and if your computer finds a prize winning prime, you share ...

A topology math puzzle?

Scott Sobel — Sat, 12 Jul 2008 05:26:30 GMT

I have a topology question (I think it�s topology related), but it may be a combinatorics question. If someone could help me with a general formula or even guidance on how to solve this I would greatly appreciate it, as it's a work question for me, not just a curiosity.

Question: How many ways is it possible to make n contiguous hyper-rectangles of size one unit or more, from a larger d-dimensional hyper-rectangle? The only restrictions are that the smaller hyper-rectangles must be at least ...

Who do we have here?

Admin — Wed, 09 Apr 2008 14:08:49 GMT

Hi everyone,

Just wondering. Where is everyone from? Does anyone work in math?

Thanks,

Chris

Mark, from New Jersey

mark.herrmann — Mon, 18 Aug 2008 21:38:13 GMT

Hello, all.

I had joined this SIG in April, but for one reason or another, I'm just getting around to peruse the board. This seems like a logical place to make my first post.

I currently work as a civil engineer, specializing in hydrology, hydraulics, and water resource management, which includes sanitary and storm sewer, as well as potable water distribution. I focused mainly on land development, but of course, that part of the industry has slowed considerably.

I've always loved ...

You might be a mathie if...

RDBury — Mon, 28 Jul 2008 01:48:08 GMT

Here are few in the style of Jeff Foxworthy's "you might be a redneck if..'' only applied to 'mathies'; You can find more in a similar vein (with some possible overlap) at http://www.mathmo.org/test/mathmotest.html.

You might be a mathie if...

* You have ever tried to explain to someone what a M�bius strip is.

* You have ever tried to explain the G�del incompleteness theorem to someone.

* You know how to correctly pronounce the '�' in M�bius and G�del.

* You have ever the answered ...

foundation of

Burt — Wed, 09 Jul 2008 13:45:48 GMT

Natural numbers are based on the assumption that the unit (1) in 1+3=4 and the unit (1) in 1+4=5 are identical. That is, all units (1�s) are identical. At one time the errors associated with grouping similar items into categories (sets) through induction such as apples, cattle, wheat, etc, were insignificant, compared to the advantages. An average was determined for each category and new items could be compared to the average and assigned to a category (deduction). As long as the base unit was ...

A topology math puzzle?

Scott Sobel — Sat, 12 Jul 2008 05:26:05 GMT

Greetings From Rich Bury

RDBury — Fri, 11 Jul 2008 01:48:15 GMT

Hi, my name is Rich Bury and I just joined yesterday. I was going for a Ph.D. in math but my career took a sharp turn and I now work with databases. I still have an interest in mathematics and I'm a frequent contributor to the math pages on Wikipedia. At the moment I'm interested in the geometry of curves, e.g the catenary, lima�on etc. Anyway, the group looks interesting and I'm sure I'll enjoy it.

How far from the corner?

Gaflin — Fri, 18 Apr 2008 00:24:34 GMT

This is one of my new favorite puzzles.

Imagine a point, P, inside a rectangle, with corners labeled A, B, C, and D in a clockwise direction. P is 6 feet from corner A, 2 feet from corner B, and 7 feet from corner C. How far is P from corner D?

Candy in Colorado

Candy Harvey — Wed, 23 Apr 2008 04:34:02 GMT

I've been a professional astrologer for over 25 years so I use the math everyday. Great to not have to do those calculations by hand like in the old days. I always worked as an engineering secretary, or for an actuarial firm or even doing construction estimates from BPs. I also design and install drip irrigation so I work with a lot of figures regarding water usuage, flow, plant spacings, etc. for efficiency and cost effectiveness in small scale sustainable agriculture.

Candy

Mike from Florida

mikez23 — Wed, 18 Jun 2008 22:12:57 GMT

I live in Florida and have been a math professor at liberal art colleges in the Midwest. Now I am a computer programmer. I will be starting the Masters program this fall in Computer Science. I have a website at www.nakedprogrammer.com that has a page on Lucas Numbers which are an extension of Fibbonacci numbers.

I also have a page on Dynamic Programming which is from Computer Science. Speaking of which, I am the moderator for a new Sig the Computer Science Sig. You can join by emailing me ...

New Topic suggestions

Robert.Hamill58 — Tue, 15 Apr 2008 13:09:09 GMT

Admin or shall I call you Wily -

I find Monte Carlo models interesting. I have a few of my own - in math and in financial modeling.

Two other areas worth considering for topics are logic and applied math.

Robert

Any actuaries out there

Admin — Fri, 04 Apr 2008 13:22:05 GMT

I am an actuarial student working in worker's compensation insurance. I am getting ready to take exam 3, and just wondered if there are any other Mensan actuaries.

Chris

Are we finished here?

ratboy — Wed, 14 May 2008 01:23:00 GMT

Not much action lately -- is there anything left to say?

Math in the Media

Seven Bridges of Koenigsberg

Robert.Hamill58 — Wed, 30 Apr 2008 02:54:29 GMT

I remember reading about this problem and Euler's solution when I was about 20. I believe it was Eric Temple Bell's Men of Math. It was my introduction to topology. Somewhere I got a translation of his paper. It was a nice, clean, and clear solution to something that was mathematical but didn't start with equations. Very accessible.

Although in a different area, Archimedes' Sand Reckoner is also accessible and makes comprehensible some limitations of the ancient numbering system.

Trigonometry?

Gaflin — Tue, 22 Apr 2008 04:37:22 GMT

Thank you, Chris, for starting this forum. Will be able to do more with this when I return home this week from out-of-town work.

I would like to suggest a trigonometry section. One of the problems in Surveying that continues to intrigue me is the Three-Point Resection. This problem concerns finding the coordinates of an unknown point, given the angles it makes with three known points. There are several methods for solving this problem and I am always on the lookout for more.

Monte Carlo - Example

Robert.Hamill58 — Thu, 17 Apr 2008 04:21:05 GMT

You've probably seen portfolio projections that use a constant percentage of growth each year. That's clearly a major simplification.

What if you got two bad years in a row right at the start of your projection period?

In the Monte Carlo simulation, one of the five ranges of actual S&P 500 yearly change is randomly selected for each year. Five parallel simulations are run for 10 and 20 years so that you can see cumulative effects.

After 20 years, your portfolio can vary by ...

New Personal Finance Website

Admin — Mon, 21 Apr 2008 20:13:40 GMT

Didn't really know where else to put this, and this forum needed a post, so...

I just started a Personal Finance Blog. I work as an actuary, so I have learned a great deal about financial mathematics. Along the way, I have learn a lot of ways to reduce your bills, invest wisely, make extra money, etc.

Everyone is welcome to stop by and have a look. I welcome any comments or suggestions.

Click Here

Thanks,

Chris

Here are my favorites!

Admin — Fri, 04 Apr 2008 15:50:48 GMT

A Mathematician, a Biologist and a Physicist are sitting in a street cafe watching people going in and coming out of the house on the other side of the street.

First they see two people going into the house. Time passes. After a while they notice three persons coming out of the house.

The Physicist: "The measurement wasn't accurate.�

The Biologists conclusion: "They have reproduced."

The Mathematician: "If now exactly one person enters the house then it will be ...

Geometry Deserves An Entry

Robert.Hamill58 — Fri, 18 Apr 2008 00:53:29 GMT

Ari Lox

by Robert Hamill

Arithophilus Loxodrome sat comfortably in the window seat of an intercontinental jet. Flying at 31,143 feet (9492 meters) above the southernmost tip of the five freshwater lakes that were formed by the retreating glaciers of the Pleistocene Epoch, Ari wondered to what distance his natural ocular mechanism could allow him to observe the horizon? And just what portion of this vast hydrated sphere, the third planet of a G type star, was available for his sensory ...

Math images

Admin — Sun, 06 Apr 2008 15:15:00 GMT

I love math images. Chaos and Topology generate some very interesting graphs and pics. I have started creating the gallery, but haven't gotten very far. You can see the three I have if you click on Gallery at the top of this page, and then click on the folder there. Does anyone have any suggestions from any area of math?

Improvements - View Recent Posts

Admin — Sun, 13 Apr 2008 14:25:38 GMT

Hi Everyone,

I knew this forum was difficult to navigate, but couldn't place exactly why. Then, I was on another forum, and realized that there was no way here to view the most recent posts. I was searching through all the posts to find anything I'd missed since the last visit. So I programmed a Recent Posts Menu Button at the top of the page. I hope this helps.

Please let me know if you have any suggestions.

Thanks,

Chris

Admin — Sun, 13 Apr 2008 14:28:51 GMT

Anyone have any suggestions for a Mathematics Newsletter. This is generally part of any SIG, but I was trying to wait until we got up and running to see what everyone's interests are. I would start out with Math News, Puzzles, Images, etc. Any other sections you would like to see?

Thanks,

Chris

Free Math Software

ratboy — Sun, 13 Apr 2008 08:04:35 GMT

Digital Math

MathCad Software

Robert.Hamill58 — Tue, 08 Apr 2008 05:43:54 GMT

I've used MathCad occasionally over the years. It usually frustrates me and I go back to writing my own custom programs. MatchCad 2001i did have a nice upgrade to converting its output to html and embedded XML.

Your interests?

Admin — Fri, 11 Apr 2008 13:58:58 GMT

Hi everyone,

Anyone have any particular math interests? I have been out of grad school for two years, but can't let go of the topology and dynamics, reading, writing a little software, just for fun. Anyone have any similar pet projects?

Chris

Fields Medal

Admin — Sun, 06 Apr 2008 15:26:10 GMT

Since I don't work with other Mathematicians, I don't hear a lot of current events in math. However, one of the most interesting to me was Grigori Perelman. In 2006, he solved the Poincar� conjecture, and then basically disappeared. This was one of the Millenium Problems, 7 math problems with a million dollar prize attached. He declined the money. He was also awarded the Fields Medal. He declined the award. Any thoughts?

Of course the money would be nice, but I would love for once ...

Hall of Fame

Robert.Hamill58 — Wed, 09 Apr 2008 02:49:59 GMT

Hall of Fame

by Robert Hamill

In Nirvana, there is a curious skyscraper. It's a hodgepodge of primitive functionality, medieval craftsmanship, productive classicism, flowery rococo, and austere modernism. The building is the home of the greats of science and mathematics.

The basement is rough and approximate. The methodical wedges of Babylonian cuneiform cover the lower wall, while colorful Egyptian hieroglyphics decorate the upper portion.

The first floor, laid out ...

Canter Sets

Admin — Wed, 09 Apr 2008 14:16:43 GMT

Anyone have any experience with Canter Sets? I studied them as an undergrad project. Really interesting, but I wish I'd gone further. I have come across them so many times since then. It really seems like there is so much I am missing. They are like pi or e, complex and interesting in their own right, and they keep showing up in strange and diverse places.

I started out studying the Cantor Middle-Thirds Set, and the Devil's Staircase function on that set. It seemed to be going somewhere, ...

Local Mensa Groups

Admin — Wed, 09 Apr 2008 14:10:16 GMT

Hi Everyone,

I haven't been in Mensa very long. Just wondering...you any of you go to your local Mensa meetings? What do you do in your meetings? Enjoy the local interaction, or interact mostly online?

Chris

New Members

Admin — Wed, 09 Apr 2008 14:21:52 GMT

Hi Everyone,

I am excited that we got so many members, so quickly, and conversation is starting to pick up. I'd love to get some more members to add more postings and keep it interesting. Any ideas? It will be going out in the Bulletin in June.

Thanks,

Chris

Favorite Math Puzzles

Admin — Sun, 06 Apr 2008 15:32:28 GMT

It seems most people who love math also love logic and math puzzles. Anyone have any favorite puzzles. I hated the Sudoku puzzles, mostly because of the quick popularity, until I worked one. They are fun and addictive. I also like the logic puzzles that come in a triangular grid with clues. I used to work these in high school. Haven't come across many good puzzles in the last few years.

In the Year 2525

Robert.Hamill58 — Tue, 08 Apr 2008 05:46:12 GMT

Here's a little puzzle I wrote:

The song wonders, �In the year 2525, if man is still alive . . . �

In what year must man be alive to hear the cicadas and see Halley�s comet in the same year?

Background:

The cicadas last appeared in 2004 and return every 17 years.

Halley's Comet last appeared in 1986 and returns every 76 years.

The Henon Map

Admin — Fri, 04 Apr 2008 13:24:19 GMT

Hi guys,

I am studying dynamical systems in my spare time. Currently, I am writing software, and trying to learn more about the Henon map. Anyone have any experience in this area or in dynamical systems in general?

Chris

Undergraduate Math

Admin — Fri, 04 Apr 2008 13:31:13 GMT

I have been asked by my alma matter, WVUIT, to sit on their advisor board this fall. This board will help to redesign their curriculum for the next few years. Anyone have any thoughts on this? I have a few ideas of how to improve current undergraduate curriculums, but I would like to get some suggestions, and see what other people think of my ideas, before I meet with them.

Chris

Math User Since 2nd Grade

Robert.Hamill58 — Mon, 07 Apr 2008 23:16:13 GMT

Hi,

I'm more a math user than a theoretician. I like applying math to scientific and economic issues.

When I was in the 2nd grade and learned the 2 times table I was fascinated. That you could do the same operation over and over again forever - and there were patterns to the results. I filled a marble copybook with 2 x 1, then 2 x that and that again until each result formed more than one line and then multiple lines. My mother said please you're wasting paper, but I was hooked.

Robert

Algebraic Topology

Admin — Fri, 04 Apr 2008 15:46:15 GMT

This is my first love in Mathematics. A beautiful subject that is still fairly new and unpursued. It is just now finding applications and gaining popularity. Anyone studied algebraic topology: homotopy, homology, cohomology?

Chris

Polyalphabetic Ciphers

Admin — Fri, 04 Apr 2008 13:28:25 GMT

Anyone have any experience with cryptography? I don't have the time to go too deep into number theory to work with RSA or anything of that nature, but I have read a few books on simple ciphers, and have written a simple program to handle polyalphabetic ciphers. I choose them because they are the one code system I have found that is perfectly invulnerable to passive attacks. I have even incorporated them into some of my programs to handle registration of software. Anyone have experience / ...

Hello fellow math geeks

joeiii63 — Sat, 05 Apr 2008 04:25:43 GMT

I am a construction foreman, framing large custom houses mostly, and I use mathematics in many forms (from arithmetic to trigonometry) on a daily basis. I have always had fascination with the power of math and find it to be a rather fulfilling hobby. I am quite good at writing complex algorithms to solve intricate design problems. I am currently using a TI 83-Plus for my programs. Even though I have no formal training or education in math, I just can't get enough of it!

Introduction for Abby

awinthrop — Thu, 03 Apr 2008 22:26:33 GMT

hey guys,

So the truth is, I love math. My father has a PhD in mathematics, and I was raised in a household filled with lots of math. This led me to get a degree in Mechanical Engineering from Johns Hopkins, then a degree in Aeronautics from Caltech. Sadly since graduating years ago, I have not used math very much. I do a lot of math puzzles in my spare time, but that's about it. I have lots of interests outside math and am actually quite social - but am excited to maybe "talk ...

Wow that was fast!

Admin — Fri, 04 Apr 2008 13:41:33 GMT

This is the first forum I have set up, and within 2 hours of posting it on the Mensa board, we had 5 members.

I hope we can keep up the momentum and get some interesting conversation in here. Great things happen when you get half a dozen viewpoints on a subject.

Please let me know if you have any suggestions for the site.

Thanks,

Chris

Free Software

Admin — Fri, 04 Apr 2008 13:20:12 GMT

I am a programmer, and I would like to get some thoughts / advise from you all. I have written several programs for my own use such as a program to graph dynamical systems, a cryptography program, a neural network program, a pi calculator, and several other simple programs. I would like to put these out there freely available, and maybe even get collaboration on improving or developing some of them. I thought this would be a great place to do that. But, the forums offer discussion and a gallery, ...

terms and conditions

maestrojce — Thu, 03 Apr 2008 22:16:22 GMT

I reviewed the terms and conditions upon registering, and I noted where it said that we may not encourage illegal activities. Does that include dividing by zero?

--jonathan

Welcome to the Mathematics SIG Forum

Admin — Thu, 03 Apr 2008 19:26:50 GMT

Hi Everyone,

My name is Chris Johnson. I would like to welcome you all to the Mathematics SIG Forum.

Mathematics is a new Mensa special interest group, meant to promote discussion amoung Mensans on all mathematical topics - high school through post-grad, software, jobs, news, etc.

I have created a number of forums to get started. Please let me know if you have any suggestions for additions or improvement.

So, please introduce yourself, come in, and get started. Also, ...