# Barry Glassner on food

Salon’s interview with Barry Glassner is really interesting. What’s nice is that he brings up the way in which the organic/healthy/no-trans-fat/etc food movement ignores the glaring issues of class (and race, reading between the lines) that are the real problem in our society. While it would be nice if we ate healthier, these healthy meals have to be affordable and efficient to those with the fewest resources (time and money) to spend on meals. I might get his book (from the library) to get more of the details.

(via Winnie’s post at get in my belly.)

# scaling laws as comedy

[Note : imagine B is from India.]

A: Oh my God!
B: What is it?
A: I just proved this great result!
B: Really???
A: Yeah, it’s an lower bound on the achievable rate!
B: So what is it?
A: Well my scheme shows it’s at least log! Log(N)!
B: Ok…
A: Isn’t that cool?
B: Seems a bit… low.
A: Well it’s not polynomial…
B: Hardly. Log(log(N))? You’ve got to be joking.
A: C’mon! Look, if you have a log, log(N) growth you can bootstrap that up to something better.
B: No you need to get rid of a log.
A: I did get rid of a log! It’s an improvement on Singh et al.
B: So it was log log log before?
A: No, log log.
A: Well it’s log log…
B: Exactly! Log log!
A: By log, do you…
B: Log log by log?
A: No, you have an extra two logs in there, it’s…
B: 1 by log? What the heck are you trying to prove!
A: It’s log! Log! Log!
B: I give up. Why don’t you come back when you’ve figured it it out. See if you can get it to log(N). [exits]

# new paper : deterministic list codes for state-constrained AVCs

It should be up on ArXiV later today…

A.D. Sarwate and M. Gastpar
Deterministic list codes for state-constrained arbitrarily varying channels
Submitted to IEEE Transactions on Information Theory
ArXiV cs.IT/0701146

The capacity for the discrete memoryless arbitrarily varying channel (AVC) with cost constraints on the jammer is studied using deterministic list codes under both the maximal and average probability of error criteria. For a cost function $l(\cdot)$ on the state set and constraint $\Lambda$ on the jammer, the achievable rates are upper bounded by the random coding capacity $C_r(\Lambda)$. For maximal error, the rate $R = C_r(\Lambda) – \epsilon$ is achievable using list codes with list size $O(\epsilon^{-1})$. For average error, an integer $\lsym(\Lambda)$, called the \textit{symmetrizability}, is defined. It is shown that any rate below $C_r(\Lambda)$ is achievable under average error using list codes of list size $L > \lsym$. An example is given for a class of discrete additive AVCs.

# yet another test

I can only hope that this Gaussian will appear:

\mathbb{P}(X \le x) = \int_{-\infty}^{x} \frac{1}{\sqrt{2 \pi}} \exp(- y^2/2) dy

How to do it:

1. Install the WP-Cache plugin. Note that you have to muck with file permissions and it’s somewhat non-intuitive.
2. Install the MimeTeX plugin.
3. Stress out about the fact that for some equations the terminating quote ” in the alt tag for the image has turned into a fancy quote. Come up with a hack involving placing an empty img tag right after every piece of LaTeX. Hope that you figure out a way around it.

# not again!

Since I only recently started reading ArXiV through my RSS aggregator, I was a unaware of the astonishing regularity with which “proofs” of polynomial-time algorithms for NP-complete problems are proposed. Most recent is this one, but one can find a more comprehensive list here. The latter page is a bit too unskeptical of the claims, since they say “so and so proved P=NP in this paper.” It’s not a proof if it’s wrong, and pretty much all of these proofs have been shown to be wrong. But it might be an interesting exercise one week for some reading group or topics class to formally prove some of these guys wrong. Of course, for every person claiming a proof that P=NP there is another person ready to knock them down and claim that P!=NP. Maybe it’s just a little self-correcting mechanism in the ArXiV.

# one thing that xmh got right

At MIT I used the xwindows program xmh to read my email. It was a pretty bare-bones program, but had one really great feature. Instead of having to drag a message to a folder to refile it, you could just right-click on the folder title and it would mark it as beign destined for there. Then you could commit all of the moves in one fell swoop. Neither GMail nor Thunderbird nor Mail.app seem to have this feature, which I regarded as a genius piece of interface in what was otherwise a pretty ugle program, all told. Maybe I’m the only one who got a lot of mileage out that feature, but I can’t help but think that our modern mail clients are missing something.