Low Dimensional Topology

October 4, 2009

Communicating Topology in the 21st Century

Filed under: Misc.,Pedagogy — Nathan Dunfield @ 1:45 pm

Because of the importance of pictures in low-dimensional topology, communicating electronically with with collaborators, students, etc., has some special challenges. (Not that other mathematicians have it easy — I’d hate to have send lots and lots of equations via email.)

Here’s some useful tools/ideas for dealing with this, some of which I use myself, and others which I’ve only heard about.

The first set is for communicating images while talking on the phone (or Skype, etc.)

  • Web whiteboards allow several people to sketch things with the mouse so that all can see the results. The one I use, at Jordan’s suggestion, is Vyew. Personally, the problem is that I can’t draw fluently with a mouse. I have a Wacom tablet, but I don’t use it enough to get past the look-at-the-screen-not-my-hand issue. These things work much better, I’m told, with a tablet computer or a Cintiq, but these aren’t cheap and I’ve never sprung for one.
  • Do a video chat, draw on a piece of paper and hold it up to the camera. Tara Brendle says that this work ok.
  • In Dublin, Noel Brady mentioned eBeam, which turns an ordinary whiteboard into a giant electronic slate. (They also have a version that works in conjunction with a projector.) Not cheap, starting at about $800.

For emailing pictures, one can always draw on a sheet of paper and then scan it in. This works pretty well; my department’s photocopiers have a neat feature where they’re email you a PDF instead of making a paper copy. The results look good and the file size is very small, so much so that I’ve started scanning all my lecture notes.

Finally, if you use a Mac, you need Skitch. It’s a little program that allows you to effortlessly grab anything off the screen, annotate it with some simple drawing tools, and export as PNG, PDF etc. Rather that try to describe why it’s just so useful, watch the 3 minute demo.

The topology groups at Iowa and LSU apparently have a regular electronically joint seminar, using some software created by the NSF. Some day I’ll have to see it in action.



  1. If Skitch is free, maybe it’s worth it, but Mac users have built in support for all that already. Indeed, SHIFT+COMMAND+4 (hold down the shift and command keys, and then click the 4) allows you to select any rectangle from the screen and make it into a PDF. And Preview’s “Annotate” menu (under “Tools”) lets you add rectangles and ovals and text notes and links.

    Comment by Theo — October 4, 2009 @ 2:18 pm | Reply

    • Yes, Skitch is free (as in beer). The point is not that what it does is at all original, but rather that the interface is so seamless and easy to use that I find my using it all the time. (As opposed to the method you mention, which I could only be bothered to do on rare occasion.)

      Skitch also has a possibly useful web-publishing component that I haven’t used but might be very useful to some.

      Comment by Nathan Dunfield — October 4, 2009 @ 2:30 pm | Reply

  2. There’s also Dror Bar-Natan’s solution: http://katlas.math.toronto.edu/drorbn/bbs/

    Comment by Noah Snyder — October 4, 2009 @ 2:32 pm | Reply

  3. Adobe has a free web conferencing service called connectnow (http://www.adobe.com/acom/connectnow/, which includes a white board feature. I haven’t tried it yet, but Adobe usually makes good products. (Don’t confuse this with Acrobat connect, which is not free.)

    Comment by Jesse Johnson — October 5, 2009 @ 11:05 am | Reply

  4. The LSU-Iowa Virtual Seminar uses Access Grid for audio and video of the audiences and speaker while we all VNC to view a desktop with a pdf that the speaker pages through. Attending a talk live where you can see everyone and they can see you is different than just watching a recorded video of a talk… it has a way of connecting you with that community. Giving such a talk is something of a different experience too.

    Comment by Ken Baker — October 6, 2009 @ 7:47 pm | Reply

  5. I use Xara Xtreme, but it takes forever. The pictures are much prettier than I would get drawing by hand, though. I don’t have easy access to a scanner, and sending photographs is too much trouble.

    Comment by Daniel Moskovich — October 7, 2009 @ 1:30 am | Reply

  6. I posted a link to this on my Facebook page, where I have over 400 “friends” with many in Math and Science.

    I’ve intrigued several people with the notion that General Relativity works only on smooth manifolds. But how do we know that we DON’T live in an Exotic Sphere in 8 or more dimensions, which is smooth, but not the plain vanilla sphere that Physicists assume.

    Comment by Jonathan Vos Post — October 12, 2009 @ 11:25 am | Reply

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