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On October 12th, I saw a post by Dan Christensen on Google+ about a list of five open problems posed by the mathematician John Conway that have monetary rewards associated with them. In particular, Conway is offering $\$1,000$ for solutions (either positive or negative) to any of the problems. Here are the five problems (as stated by Conway):

  • Problem 1. Sylver coinage game (named after Sylvester, who proved it terminates): The game in which the players alternately name positive integers that are not sums of previously named integers (with repetitions being allowed). The person who names 1 (so ending the game) is the loser. The question is: If player 1 names 16, and both players play optimally thereafter, then who wins?
  • Problem 2. 99-Graph: Is there a graph with 99 vertices in which every edge (i.e., pair of joined vertices) belongs to a unique triangle and every nonedge (pair of unjoined vertices) to a unique quadrilateral?
  • Problem 3. The Thrackle Problem: A doodle on a piece of paper is called a thrackle if it consists of certain distinguished points called spots and some differentiable (i.e., smooth) curves called paths ending at distinct spots and so that any two paths hit once and only once, where hit means having a common point at which they have distinct tangents and which is either an endpoint of both or an interior point of both. The right hand figure shows a thrackle with six spots and six paths. But can a thrackle have more paths than spots?
  • Problem 4. Dead Fly Problem: If a set of points in the plane contains one point in each convex region of area 1, then must it have pairs of points at arbitrarily small distances?
  • Problem 5. Climb to a Prime: Let $n$ be a positive integer. Write the prime factorization in the usual way, e.g., $60 = 22 \cdot 3 \cdot 5$, in which the primes are written in increasing order, and exponents of 1 are omitted. Then bring exponents down to the line and omit all multiplication signs, obtaining a number $f(n)$. Now repeat.So, for example, $f(60) = f(22 \cdot 3 \cdot 5) = 2235$. Next, because $24235 = 3 \cdot 5 \cdot 149$, it maps, under $f$, to 35149, and since 35149 is prime, it maps to itself. Thus, $60 \to 2235 \to 35149
    \to 35149$, so we have climbed to a prime, and we stop there forever. The conjecture, in which I (Conway) seem to be the only believer, is that every number eventually climbs to a prime. The number 20 has not been verified to do so. Observe that $20 \to 225 \to 3252 \to 223271 \to \cdots$, eventually getting to more than one hundred digits without yet reaching a prime.

If you solve one of these, you can reach Conway by sending snail mail (only) in care of the Department of Mathematics at Princeton University.

Around the same time that I stumbled onto these problems, I was brainstorming ideas for a couple of upcoming talks that I was slated to give (one for undergraduates and one for high school students). I decided that discussing open problems with monetary rewards with an emphasis on Conway’s problems would likely make for a nice talk. Here is the abstract that I settled on for both talks.

There is a history of individuals and organizations offering monetary rewards for solutions, either in the affirmative or negative, to difficult mathematically-oriented problems. For example, the Millennium Prize Problems are seven problems in mathematics that were stated by the Clay Mathematics Institute in 2000. A correct solution to any of the problems results in a $\$1,000,000$ prize being awarded by the institute. To date, only one of the problems has been solved (the Poincaré Conjecture was solved by Grigori Perelman, but he declined the award in 2010). These are hard problems! The renowned mathematician John Conway (Princeton) maintains a list of open problems and for each problem on the list, he is offering $\$,1000$ to the first person that provides a correct solution. In this talk, we will explore a few of Conway’s problems, and in the unlikely event we come up with a solution, we’ll split the money.

On Friday, October 24, 2014, I gave a talk during the Friday Afternoon Mathematics Undergraduate Seminar (FAMUS) at NAU. Speaking at FAMUS is always fun and my talk seemed to be well-recieved.

After having a practice run during FAMUS, I was able to improve the slides I intended to use during my talk at the 2014 NAU High School Math Day, which took place a few days later on Tuesday, October 28, 2014. Here are my slides:

I had a blast presenting to the high school students. It cracked me up that there were a few students that immediately started obsessing over the Sylver coinage problem and likely didn’t hear a word I said after that. My goal was to give an engaging and high energy talk. I also slid in some humor and I was happy that everyone laughed when they were supposed to. Interestingly, the thing I said that the students thought was the funniest was something that I didn’t intend to be humorous. When I stated that “If you solve one of these, you can reach Conway by sending snail mail (only) in care of the Department of Mathematics at Princeton University,” the audience burst into laughter. Requiring snail mail seemed so ridiculous to them, they thought it was a joke.

As a side note, I used mtheme (available for free on GitHub) together with beamer/LaTeX to generate my slides. I’m really happy with the look of mtheme and thrilled to get away from the standard beamer themes.

Nice socks!

December 28, 2013 — 1 Comment

socks On page 36 of the December 2013/January 2014 issue of the MAA FOCUS there is a short article about Math Ed Matters, which is a monthly blog/column sponsored by the Mathematical Association of America and coauthored by Angie Hodge and myself. The article, written by Katharine Merow, highlights a few of our recent posts and describes some potential future posts (I should write these down, so we remember to write the advertised posts!). Katharine wanted to include a picture of Angie and me for the article, and as you can see in the picture to the left, she chose one of us that was taken after we had finished a trail run. I’m also wearing some ridiculous looking socks! The socks are actually compression socks designed for running, but they look silly nonetheless. I’ve been getting some flak for wearing such tall socks, but I think it’s funny.

I knew this article was going to appear, but I wasn’t sure when. It was brought to my attention by Robert Jacobson via one of his Google+ posts. Robert is responsible for the photo.

Dear College Instructors,

Matthew Leingang (NYU), Ron Taylor (Berry College), and I are interested in how college instructors utilize social media. In particular, we are curious how teachers interact with their current and past students on social networks like Facebook and Google+. How do you interact with your current and former students on social media? Do you have policies about this interaction? We have put together a short survey to gather some data regarding this often sensitive issue. The intent is to summarize the results in a short article that will likely be submitted to MAA FOCUS. We would be thrilled if you would take a few minutes to complete our short survey.

Thanks!

Dana, Matthew, & Ron

Stepping away from Twitter

December 20, 2012 — 2 Comments

Facebook, Twitter, Google+, Instagram, Pinterest, yada, yada, yada. Each of these social networking sites has something to offer and I have accounts on most of them. However, I think it may be time to streamline. Increasingly, I feel pressed for time to do all the things that I need and want to do. There’s an endless amount of work-related stuff to do, but I also want to be a good father and husband. Moreover, if I don’t squeeze in time for exercise, I’m not very good at anything. I’m like a dog. If I don’t get in a walk, I might chew the furniture.

I currently have two accounts on Twitter: @danaernst and @IBLMath. Why two accounts? Most of my tweets are math-related, but not all of them. I created @IBLMath for two main reasons. First, I wanted to increase awareness of inquiry-based learning in mathematics. Second, I thought it was a good idea to have an account that was solely devoted to tweeting about math and teaching-related content. At the time of writing this post, I’ve tweeted 4,445 times from @danaernst, and according to How long have you been tweeting?, I made my first tweet on March 4, 2009. Twitter has been an amazing resource for me.

Then along came Google+, which launched in June of 2011. I don’t know the exact date that I joined, but it was within the first few weeks. I connected with quite a few academics early on and now I have a substantial network of people interested in mathematics, teaching, and technology. In fact, nearly all the people that I enjoy most on Twitter are also on G+. Since my network on G+ is so much larger than on Twitter, I often encounter content on G+ that I don’t see on Twitter, but I rarely see content on Twitter that doesn’t pop up on G+. Moreover, the interaction that happens on G+ is often much more substantial than what I’ve experienced on Twitter. I regularly cross-post content on Twitter and G+ and it’s not uncommon for one of my “popular” posts on G+ to see zero attention on Twitter.

I’ve been wondering for a while now whether maintaining my Twitter presence is worth my time. One of my weaknesses is that I’m not very good at doing things part-way. I’m an all or nothing kind of guy. As a result of this, I find myself feeling anxious when I’m not caught up on surfing Twitter, G+, Facebook, etc. posts. The reality is that I don’t have time to even come close to keeping up. The rate of new content is overwhelming. My first semester at NAU has been successful, but I need to find ways to be even more efficient and effective at work, family, and play. In this vein, I’m looking for ways to trim unnecessary things from my life. I don’t plan to give up social media, but I think that I can save myself actual time and certainly some mental and emotional bandwidth by walking away from Twitter.

I’ll treat this as an experiment and see how it goes after a few months. I don’t think that I’ll miss it. I will likely continue to advertise my blog posts (from this blog and my Elevation Gain blog) on Twitter and respond to @mentions.