I left California far too quickly: some people that I had really wanted to see I didn’t get to see. But I got to spend a lot of time with my dad, which was excellent, and the conferences and Berkeley itself were a lot of fun.

I understand why clutching functions are called clutching functions: a automobile’s clutch transmits rotation from one object to another under the control of the driver, and a clutching function likewise glues together two different rotations under the control of the mathematician.

Having been gone for two weeks, the beautiful cat Tasha has decided that my chair is her chair.

I saw a poster that described a play as “crunchingly witty.” This seems like a very strange sort of wittiness to me.

Gromov, M. and Piatetski-Shapiro, I.. Nonarithmetic groups in Lobachevsky spaces. Inst. Hautes Études Sci. Publ. Math. 1988. 93–103. MR.

Vinberg, …

Margulis’ amazing arithmeticity theorem says that irreducible lattices in Lie groups of high ($>2$) rank are arithmetic. But ${\rm SO}(n,1)$ has rank 1, so a question is how to produce non-arithmetic lattices. For ${\rm SO}(3,1)$, there are non-arithmetic lattices coming from hyperbolic knot complements.

G–P-S produces higher dimensional examples by taking two hyperbolic (arithmetic) manifolds, cutting along totally geodesic hypersurfaces, and gluing. Are there are examples of non-arithmetic hyperbolic manifolds without any totally geodesics hypersurfaces?

There are complements of $T^2$’s in $S^4$ which are hyperbolic, and maybe these would provide some examples.

I am still in California, and very much enjoying public transportation. Yesterday, I took AC Transit’s 65 bus (the “Euclid” bus) along an extremely (and therefore ironically) curvy road to get off the mountain of MSRI. (The “mountain of misery” belongs in a fantasy novel.)

There’s a lot of people in California I would still like to see.

Here is a really stupid question: If I have a wire (with a changing current) and I bend it around, and measure the induced current in (a finite number of) neighboring coils, can I determine anything about how I have bent the wire? Being more ridiculous, I will weave together wires to make fabric. How do the electrical properties of the fabric relate to its shape? That is, if I run current along one wire, and measure the induced current in other wires, can I deduce anything about how I have bent the fabric?

It strikes me as amusing to measure the speed of something by, say, attaching a magnet to the wheel and then seeing how quickly the magnet is moving past a coil. I wonder how sensitive this would have to be, say, to work as a bicycle speedometer.

Anyway, this is the stuff that bothers me on the bus. Right now, it is my inability to produce more examples of hyperbolic n-manifolds that is bothering me.

I’ve made it to Los Altos: I’m going to be staying with my dad, but during the next couple weeks visiting Berkeley to go to a conference, and to meet up with my advisor.

I ended up talking Route 22 on VTATransit_Authority#Bus_routes), and then walking a few miles to go here, in the dark, using GPS to guide me. I was amazed that this method worked!

I guess I should warn you that I am about to reveal plot details of Dan Brown’s books.

I read Digital Fortress by Dan Brown, which was an unfortunate use of time. That book, for starters, is isomorphic to the Da Vinci Code; they are both about a female cryptologist, who gets involved with a university professor, who is himself dragged into a global conspiracy. Humorously, at one point, they use a 5-letter password (which just happens to the female cryptologist’s name, just like in the Da Vinci Code). And like every Dan Brown book, this book also happens to begin with someone dying, who, as the holder of a secret, tries to reveal his secret before he dies.

The more unfortunate thing was the portrayal of mathematics and computer science in Digital Fortress. Terrifying, really.

I watched Neon Genesis Evangelion this summer again, and I’m watching El Hazard now. I am extremely tempted to purchase Mysterious Cities of Gold DVD’s—does anyone else remember how awesome that was?

My cat Tasha is beautiful, and I will miss her while I am in Berkeley.

I am extraordinarily excited by the possibility that Sufjan Stevens might, in his epic quest to author a musical tribute for all 50 states, choose Minnesota next. Perhaps I am swayed by the fact that I am listening to Sufjan Stevens’ The Avalanche, and realizing again that I rather love him.

And I spend quite a bit of time brushing my teeth everyday, but I rather rarely discuss toothbrushing technique, or, for instance, how I learned to brush my teeth.