nchoosetwo and collaborative ranking

Walking around campus these days, there are cryptic-looking things like

\(\binom{n}{2}\mathrm{.com}\) and \(\binom{n}{2} \ni \binom{i}{u}\)

obviously referring to a dating site — currently it’s restricted to MIT and Harvard students. This one tries on an idea that I’ve heard discussed numerous times in different contexts, but apparently nobody went and did it in all these years. Instead of running a matching algorithm, it asks third parties (i.e. matchmakers) as well as the interested parties themselves to suggest matches. The thing that is supposed to keep this low-risk is anonymity: a match isn’t revealed until the two primary parties involved mutually accept or their lists intersect.

As with all things that involve anonymity, this asks for trollish and antisocial behavior. I’ve already registered three aliases on moira for exactly this purpose — ok, ok, so they’ve suppressed that antic after people raised concerns, though these and other ramifications should have perhaps been worked through a bit more carefully pre-launch.

The spam potential remains. A matchmaker’s identity isn’t revealed unless both people accept her suggestion, so pranks and insults can be conducted to an extent. One way around this may be grafting social graph data onto the system for collaborative filtering (if they manage to obtain such data…). And if they do, perhaps the suggestions of more closely related people should weigh more, along with those of successful matchmakers. Perhaps there should even be more weight if multiple matchmakers concur. This is extremely intriguing, because eliminating spam is equivalent to predicting who is a likely match, and collaborative filtering for this problem is an unexplored direction.

The more fundamental question is why such a site is even necessary.
(Read the article)

Csiszar & Korner

Imre Csiszar and Janos Korner are two Hungarians with very Hungarian names. But more importantly, they wrote a thrilling page-turner called, Information Theory: Coding Theorems for Discrete Memoryless Systems. It is a book most difficult to obtain. It seems that the book has been out of print ever since the day it was in print. Academiai Kiado of Budapest and Academic Press of New York (same thing?), I’m looking in your general direction(s). Hmm. I wonder if the cost structure of running a printing press is akin to that of running a chip foundry?

http://ec1.images-amazon.com/images/P/9630574403.01._AA240_SCLZZZZZZZ_.gif

Anyway, forget the publishers. There is one copy in the library, permanently checked out, on hold, or requested. Almost never seen in online stores, it sells for several times the list price when scalper123 occasionally trots it out on YahooMazonBay. Worst of all, nobody has bothered to make and distribute a pdf of it for the good of the masses. Er, wait, I mean, nobody has bothered to make a Fair Use copy for personal use.

And accidentally leave the pdf on an unprotected public server. (Please?)

Well, that was last week, and this is now. I am to this day amazed that Kazoo Books still had one (1) old, used, but perfectly good copy at list price. I wrote “had.” Good service and fast delivery, too. No fraud committed against me despite there being a phone transaction with a credit card. Highly recommend. Wait, this isn’t eBay, why am I writing this?