http://blog.mikael.johanssons.org Because my LiveJournal is too silly Thu, 19 Jun 2008 07:53:57 +0000 http://backend.userland.com/rss092 en Based on the extensive discussion at the Secret Blogging Seminar on tools for long-distance collaborations, Scott Morrison writes an introduction to source control with subversion for research collaborators. In this post, Scott also offers, quite magnanimously, to setup and host subversion repositories for any mathematician who happens to want to ... http://blog.mikael.johanssons.org/archive/2008/06/a-vision-for-collaborative-mathematics-platforms/ Jag har varit en god medborgare. Jag har börjat emaila politiker. Anledningen är gårdagens debatt och dagens återremittering av FRA-Lagen. Kärnan i mitt email, efter en personaliserad inledning där jag återknyter till vardera riksdagsledamots insats i debatten, är följande argumentation. Tanken med signalspaningen är att analysera trafikmönster, läsa innehåll, ... http://blog.mikael.johanssons.org/archive/2008/06/fra-lagen-och-falska-positiver/ I seem, lately, to be so densely planned that all I can do for my blog is to react on blog posts from Ben Webster at the Secret Blogging Seminar. He has, recently, written a post inspired by the xkcd comic on purity in the sciences. The comic is funny, and ... http://blog.mikael.johanssons.org/archive/2008/06/on-purity-and-essence-of-mathematics/ I like the Mathjobs website that AMS are running. It's a good source for math jobs, and seems to have just the right selection for me to get interesting stuff out of reading it. Now, in a post just a day or two ago, Ben Webster of the Secret Blogging Seminar ... http://blog.mikael.johanssons.org/archive/2008/06/ams-and-mathjobsorg-are-made-of-awesome/ My two high-school kids came by today. We've been trying to get a new teaching session together since early February, but they had a hell of a time all through February, and all our appointments ended up canceled with little or no notice; and then I spent March and April ... http://blog.mikael.johanssons.org/archive/2008/05/restarting-high-school-topology/ First off, I'd ask your pardon for the lull in postings - this spring has been insane. It has been very much fun - traveling the world, talking about my research and meeting people I only knew electronically - and also very intense. To break the lull, I thought I'd try ... http://blog.mikael.johanssons.org/archive/2008/05/parallell-and-cluster-mpi4py/ Edited to add Galway I'll be doing a "US tour" in March / April. For the people who might be interested - here are my whereabouts, and my speaking engagements. I'm booked at several different seminars to do the following: Title: On the computation of A-infinity algebras and Ext-algebras ... http://blog.mikael.johanssons.org/archive/2008/03/tour-dates/ I'm going to move on with the identification of geometric objects with functions from these objects down to a field soon enough, but I'd like to spend a little time nailing down the categorical language of this association. Basically, we have two functors I and V going back and forth ... http://blog.mikael.johanssons.org/archive/2008/03/introduction-to-algebraic-geometry-3-in-a-series/ I want to lead this sequence to the point where I am having trouble understanding algebraic geometry. Hence, I won't take the usual course such an introduction would take, but rather set the stage reasonably quickly to make the transit to the more abstract themes clear. But that's all a ... http://blog.mikael.johanssons.org/archive/2008/02/introduction-to-algebraic-geometry-2-in-a-series/ I'm growing embarrassed by my lack of understanding for the sheaf-theoretic approaches to algebraic (and differential) geometry. I've tried to deal with it several times before, and I'm currently reading up on Algebraic Geometry again to fill the void that the finished thesis, soon arriving travels and non-existent job application ... http://blog.mikael.johanssons.org/archive/2008/02/introduction-to-algebraic-geometry-1-in-a-series/ I saw the Cerebrate solve the first Scripting Games challenge: Pairing off. And immediately thought "I can do that in Haskell too". So, here it is. import Data.List cards = [(1,7),(0,5),(3,7),(2,7),(2,13)] countpairs [] = 0 countpairs [a] = 0 countpairs (a:as) = length . filter (((snd a)==) . snd) $ as pairingOff = sum . map ... http://blog.mikael.johanssons.org/archive/2008/02/scripting-games-in-haskell/ Brent Yorgey wrote a post on using category theory to formalize patch theory. In the middle of it, he talks about the need to commute a patch to the end of a patch series, in order to apply a patch undoing it. He suggests a necessary condition to do this ... http://blog.mikael.johanssons.org/archive/2008/02/props-and-patches/ In a mean push, these last two weeks my advisor has read three different drafts of my thesis. And I've worked on getting the corrections in quickly. The last push started yesterday, when I got a bunch of corrections in the morning, had the last draft ready at 4pm, and ... http://blog.mikael.johanssons.org/archive/2008/02/thesis-written/ So, here's the plan for my 10th grade topology students. Today, we'll abandon algebraic topology completely, and instead go into knot theory. I'll want to discuss what we mean by a knot (embedding of [tex]S^1[/tex] in [tex]S^3[/tex]), what we mean by a knot deformation (thus introducing isotopies while we're at it) ... http://blog.mikael.johanssons.org/archive/2008/02/my-topology-students-move-into-knot-theory/ At the start of the German Year of Mathematics, the Oberwolfach research institute has released an exhibition and the software they used to produce it. The software, surfer, is a really nice GUI that sits on top of surf and lets you rotate and zoom your algebraic surfaces as well ... http://blog.mikael.johanssons.org/archive/2008/01/algebraic-surface-toys/