All blackboards are gone. They were replaced during the break. (So, no chance to use this MathOverflow question on the near future.) Makes me think of T.H. Huxley’s On a Piece of Chalk (see here) and wonder what the equivalent will be in a few decades.

On the plus side, we now have computers and projection equipment on each classroom. I am using this quite a bit in my abstract algebra class. Except that, during the first few weeks, it was more often than not that the keyboard would be locked away.

Annoyed, I called OIT and asked that they please make sure it was unlocked before my class. It worked for a few days. But then, again, I found it locked.

I called again (I was charming, I am sure). So, somebody came to the classroom, looked at me, smiled. And pressed a button, to open the drawer.

Sigh.

(In my defense, the class is at 8:30 in the morning, and I’m supposed to drink less coffee these days. But still.)

(“Thanks. I’m sorry. I’m an idiot.” “Oh, no, no. It is new.” “It is a button.”)

43.614000-116.202000

Like this:

LikeLoading...

Related

This entry was posted on Sunday, February 19th, 2012 at 4:26 pm and is filed under Life. You can follow any responses to this entry through the RSS 2.0 feed.
You can leave a response, or trackback from your own site.

Have you had a chance to use a tablet+projection to replace the whiteboard? Infinite paper with infinite zoom to add additional comments in the right place is a great tool I use for taking notes, but never had a chance to use in class.

I am looking for references discussing two inequalities that come up in the study of the dynamics of Newton's method on real-valued polynomials (in one variable). The inequalities are fairly different, but it seems to make sense to ask about both of them in the same post. Most of the details below are fairly elementary, they are mostly included for comp […]

Let $C$ be the standard Cantor middle-third set. As a consequence of the Baire category theorem, there are numbers $r$ such that $C+r$ consists solely of irrational numbers, see here. What would be an explicit example of a number $r$ with this property? Short of an explicit example, are there any references addressing this question? A natural approach would […]

Not necessarily. That $\mathfrak m$ is consistently singular is proved in MR0947850 (89m:03045) Kunen, Kenneth. Where $\mathsf{MA}$ first fails. J. Symbolic Logic 53(2), (1988), 429–433. There, Ken shows that $\mathfrak{m}$ can be singular of cofinality $\omega_1$. (Both links above are behind paywalls.)

Ignas: It is not possible to provide an explicit expression for a non-linear solution. The reason is that (it is a folklore result that) an additive $f:{\mathbb R}\to{\mathbb R}$ is linear iff it is measurable. (This result can be found in a variety of places, it is a standard exercise in measure theory books. As of this writing, there is a short proof here. […]

MR2449474 (2009j:03067) Woodin, W. Hugh. A tt version of the Posner-Robinson theorem. Computational prospects of infinity. Part II. Presented talks, 355–392, Lect. Notes Ser. Inst. Math. Sci. Natl. Univ. Singap., 15, World Sci. Publ., Hackensack, NJ, 2008. The proof is nice, invoking both recursion-theoretic and set-theoretic tools. Hugh uses a Prikry-like f […]

Your idea is sound, but it requires more work. As pointed out, you have only described so far a very small subcollection of the Borel sets. Instead, show that you can associate to each Borel set a code that keeps track of the "history" of its construction starting from basic open sets, and then count the number of such codes. There is a lot of leew […]

Recently, I was reading Hardy's Orders of Infinity (available here or here): Godfrey Harold Hardy. Orders of infinity. The Infinitärcalcül of Paul du Bois-Reymond. Reprint of the 1910 edition. Cambridge Tracts in Mathematics and Mathematical Physics, No. 12. Hafner Publishing Co., New York, 1971. MR0349922 (50 #2415). The book discusses this result, so […]

There is no slowest divergent series. Let me take this to mean that given any sequence $a_n$ of positive numbers converging to zero whose series diverges, there is a sequence $b_n$ that converges to zero faster and the series also diverges, where "faster" means that $\lim b_n/a_n=0$. In fact, given any sequences of positive numbers $(a_{1,n}), (a_{ […]

What you are attempting is not possible in general. Here is a counterexample: It is consistent (modulo large cardinals) that dependent choice holds, but full choice fails, and the club filter is an ultrafilter on $\omega_1$. Since the club filter is countably complete, it follows that in such a model, if we partition $\omega_1$ as $\bigcup_n B_n$, then exact […]

This is quite hilarious (I sympathize).

Have you had a chance to use a tablet+projection to replace the whiteboard? Infinite paper with infinite zoom to add additional comments in the right place is a great tool I use for taking notes, but never had a chance to use in class.

I haven’t, but I probably should. I’ve heard Hugh Woodin uses this quite effectively teaching precalculus, of all things.