Archive for July, 2011

July 31, 2011

The etiquette of old age does not seem to have been written up, and we have to learn it the hard way. It depends on a basic realization, which takes time to adjust to. You must realize that after reaching a certain age you are no longer viewed as a person. You become an institution, and you are treated the way institutions are treated. You are expected to behave like a piece of period furniture, an architectural landmark, or an incunabulum.

It matters little whether you keep publishing or not. If your papers are no good, they will say, “What did you expect? He is a fixture!”; and if an occasional paper of yours is found to be interesting, they will say, “What did you expect? He has been working at this all his life!” The only sensible response is to enjoy playing your newly found role as an institution.

Gian-Carlo Rota


July 30, 2011

Violin Strobe by Henry Flynt

Job Postings

July 29, 2011


XXX is seeking a high-caliber, experienced YYY with proven research, development and application skills in the area of ZZZ. The selected candidate will have a track-record of creating innovative YYY solutions to industry business challenges. They will also enjoy working in a collaborative environment with multi-disciplinary research teams, service team, business unit and vendor partners, testing and applying new technologies for direct business impact.

So many job postings sound like this. Overly formal, clearly written by someone unfamiliar with the kind of work the sought-after employee would be doing, and filled with suggestive but vapid jargon.

Who does XXX think they will attract with this kind of language? I can think of two kinds of people who would sincerely respond, “Yes, that’s me!” to the above statements: unoriginal toadies and liars.

Plain English. Let’s use it.

July 28, 2011

I will only touch you once.
And it will only be in passing.

Tangent by Eugene Guillevic, from the collection Geometries (via komurki, hannahfiddell)

Boundaries and Flows

July 27, 2011

Gauß’ divergence theorem states that, unless matter is created or destroyed, the density within a region of space V can change only by flowing through its boundary ∂V. Therefore

i.e., you can measure the changes in an entire region by simply measuring what passes in and out of the boundaries of the region. “Stuff passing through a boundary ” could be:

  • tigers through a conservation zone (2-D)
  • sodium ions through a cell (3-D)
  • magnetic flux through a toroidal fusion chamber
  • water through a reservoir (but you’d have to measure evaporation, rain, dew/condensation, and ground seepage in order to get all of ∂V)
  • in the other direction, you could measure water upstream and downstream in a river (no tributaries in between) and infer the net amount of water that was drunk, evaporated, or seeped
  • probability mass through a set of possibilities
  • particulate pollution through “greater Los Angeles”
  • ¿ ideas through your head ? ¿ electrical impulses through your brain ? ¿ feelings through your soul over time ?
  • ¿ notes through a symphonic orchestra ?
  • chromium(VI) through a human body
  • imports and exports through an economy
  • goods or cash through a limited liability company

Said in words, the observation that you can measure change within an entire region by just measuring all of its boundaries sounds obvious, even trivial. Said symbolically, Gauß’ discovery amounts to a nifty tradeoff between boundaries  and gradients . (The gradient  is the net amount of a flow: flow in direction 1 plus flow in orthogonal direction 2 plus flow in mutually orthogonal direction 3 plus…) It also amounts to a connection between 2-D and 3-D.


Because of Cartan-style differential geometry, we know that the connection is much more general: 1-D shapes bound 2-D shapes, 77-D shapes bound 78-D shapes, and so on.

Nice one, Fred.

July 26, 2011

Geometric minimal | Illustration on the Behance Network via planetaryfolklore via thirstyear

July 25, 2011

one million flowers by Holger Lippmann (via holgerlippmannwowgreat)

July 24, 2011

what are we to make of those statistically-minded disciplines currently obsessed by the search for ever more complicated models, to be summarized in terms of endless tables of coefficients and other statistical paraphernalia, and often with scarcely a graph in sight, whether of original data, model results or model diagnostics?

Leland Wilkinson, The Grammar of Graphics

The Hardest Sport

July 23, 2011

“Hitting a baseball is the hardest thing to do in sports.” —Ted Williams

On the subject of noncommutative things from everyday life: what’s the hardest sport? People love to debate this question. Fans with a favourite sport say their athletes are the fastest, strongest, most adept, or otherwise better than athletes from other sports. These disputes se basan the television show Last Man Standing, which pits strongmen against outdoorsmen against finesse athletes against … yoga instructors? Well, I’ve even heard the argument made that skateboarding is the most difficult sport.


One way to justify that one sport is more difficult than another is to measure how long it takes for sportsman A to master sportsman B’s sport and vice-versa.

This gives rise to a connected graph with sports at each node. Suppose an objectively hardest sport exists — i.e., it is easier to transition from Calvinball to another sport than the reverse, for every sport which is not Calvinball.

Even if such a sport exists, there’s no reason to think that the graph would look at all symmetrical, transitive, or obey other nice mathematical properties. addition or composition would be obeyed on the graph. In the scenario I drew above, the ease with which a Calvinballer can transition to another sport tells you very little about how easy it is for an athlete from Sport S to transition to Calvinball. One could measure difficulty of a sport other than Calvinball either by how hard it is for a Calvinballer to transition to it, or by many other measures (aggregate or individual).


It would be more accurate to put individual athletes at each node rather than “a sport”. That I can mathematically write down either scenario shows how varying levels of abstraction (even prejudice) can be incorporated into a mathematical model.

July 22, 2011

Bushwick Blues by Delta Spirit