Happy May 5! Today is not actually Mexican independence day, but it is the anniversary of a major battle between Mexico and France. Popular confusion over the reason for the celebration won't keep any number of people from celebrating, of course. The weather, on the other hand, might be an impediment. It's raining here. It's also sufficiently close to the end of the semester that a large fraction of those I see on my daily walks about campus look like tired, worried, or both.
I last wrote anything here on April 11. Since I'll be traveling for most of the last half of this month, I probably won't write anything then. For a moment, though, I need to write something that involves no formulas and no code. I love continuum mechanics; I think differential geometry is grand; and I think simulations of coupled-field interactions are wonderful. I also think I need a brief respine from trying to simultaneously reference too many papers and texts in which E stands for energy, Young's modulus, the electric field, the Lagrangian relative strain tensor, an orthonormal basis for a referential coordinate system, and a generic measurable set. Epsilons are similarly overused.
There's a classic reference by Truesdell and Noll, The Nonlinear
Field Theories of Mechanics which, near the beginning, has most
of a page devoted to which fonts and alphabets are to be used to
denote different types of mathematical objects; the following several
pages are a glossary of frequently-used symbols. Unfortunately, while
I know the Greek and Roman alphabets, I don't know the Hebrew alphabet
and I have trouble deciphering characters in ornate Fraktur fonts.
The first time I saw a formulae involving both a Fraktur F (I think it
was an F) and a resh (which looks sort of like a backward capital
gamma) subscripted by a capital gamma, I remembered the whole thing as
sum of meow-meow of strange-meow-sub-gamma. I
forget what happened next, but I probably decided that it was time to
take a walk.
I know a few people who feel very strongly that books and papers
should be read in a strictly sequential manner, starting at the
beginning and proceeding line by line through the end. For my own
part, I have no qualms on a first reading with mentally replacing all
the formulas in a paper with
meow-meow-meow (or perhaps
meow-meow-meow, which is some complicated function of position but
not time). In areas of sufficient familiarity, I read formulae in
the same way I read words, by looking at the shape rather than at the
individual characters. But when an unfamiliar formula appears, the
words can -- and usually do -- give a sufficient sense of what's going
on that it's possible to understand the big picture even with an
Similarly, I don't mind overmuch if I tell someone about something I
find interesting and they hear something like
from time to time. That's part of learning. On the other hand, I
find it intensely annoying to spend the effort to speak my thoughts,
only to realize that the listener turned off his brain immediately
after the first unfamiliar word. This is nearly as annoying as trying
to inform someone who
knows you're wrong, and therefore doesn't
bother to listen. Was it Will Rogers who said
it's not what people
don't know that's the problem, it's what they know that just ain't
It's a good thing I'm not a politician.