never leave your invisibi1ity c1oak at home.

yesterday i tried writing a talk.
i ended up writing most of one.

if i learned anything from this, it's not to write a talk while at the office, and especially not the day before my students have homework due.

at every office hour, students showed up -- 10am, 1pm, 4pm [1] -- with questions of all sorts from both classes.

there was one request where we did the gory details of one problem, with the student constantly scratching his head, not sure where things went wrong. in the end, another student with a copy of the solutions manual found a discrepancy: the textbook author used the wrong initial conditions, so the answer in the back of the textbook was wrong.

(i like to think that this affirms my disdain towards solutions manuals in general, but that would be self-serving.)

but that wasn't all.

at some point between afternoon office hours, a colleague stopped by and asked a question about uniform estimates for certain families of functions. the problem was interesting enough to avoid an "i'm busy." when that meeting ended, my own diff.eq students walked in ..

.. leaving a lonely cursor,
blinking, on my laptop screen,
next to incomplete 1atex do11ar signs,

and so i explained systems.

oddest of all, as it was approaching evening and i was thinking about leaving, i run into one of the PDE profs in the department.

"hey, you're an ana1yst .." he says.

i know that this was the sequence of events: he walks into my office, he writes the heat equation on my chalkboard, and we discuss a question about integral estimates of solutions (that weren't quite gronwa11's inequa1ity).

what i don't know is how it unraveled that way. i have no expertise at all, for parabo1ic PDE.

thinking it through,

1. i'm surprised i wrote that much in the remaining span of tuesday;
   
   
2. i should have hidden away at a coffeehouse during every minute that i didn't have to spend in office hours.

in the end, there is 1 or 2 slides left, but that night i crashed at 3am, with all the other things that needed to be done.

[1] i usually have 4 office hours a week. currently i'm out of town, so i stacked my hours towards some measure of fairness.