J. John Sepkoski, Jr., was a fossil-hunter who did most of his digging in the library, sifting through the literature of paleontology to build a detailed, quantitative timeline of life on earth. Focusing on marine animals, he recorded the earliest and the latest known appearances of thousands of ancient organisms. The final edition of his […]
In my latest American Scientist column I advert to a famous passage in Leibniz (translation by Robert Latta, 1898):
When controversies arise, there will be no more necessity of disputation between two philosophers than between two accountants. Nothing will be needed but that they should take pen in hand, sit down with their counting tables and […]
Riffling through some file folders last night, I happened upon an item that I evidently clipped out of Datamation years ago. It’s titled “Magic Moments in Software,” by Deborah Sojka and Philip H. Dorn. I can’t find a date on any of the pages, but internal evidence suggests it’s from the early 1980s.
The piece […]
As I mentioned, the American Scientist web site is undergoing an overhaul. One aspect of the transition that’s still in transition is redirecting http requests so that old links and bookmarks will retrieve the correct document on the new site. I wish I could snap my fingers and fix this problem globally, but that seems […]
Theorists and theologians of programming languages give a lot of thought to issues like referential transparency, lexical scope rules and idempotency. More often than not, though, programming languages live or die for reasons that have nothing to do with such syntactic and semantic virtues. In the early 1980s everyone wrote programs in Microsoft BASIC because […]
Imagine an unending stream of names:
Britney, Brad, Angelina, Britney, Pamela, Jessica, Jessica, Britney, Clay, Brad, Britney, Britney, Pamela, Clay, Brad….
Your job is to keep a running tally of the number of unique names. (The snippet above, with 15 names altogether, has 6 unique names.)
There’s a straightforward method of solution: Keep a record of all […]
When I finished writing about the Zeno wagering game recently, I had some trees left over, so I thought I would try planting them here.
In the Zeno article I was trying to understand and explain the structure of this peculiar-looking tree, which I’ll call the tangled tree:
As a warmup exercise, I started out with […]
The latest issue of American Scientist is just out, both on the newsstand and on the web. My “Computing Science” column is titled “Wagering with Zeno”; it returns to a subject mentioned briefly in an earlier column, “Follow the Money.”
Consider a random walk on the interval (0,1), where the walker moves according to these […]
Leslie G. Valiant, whose work on holographic algorithms was the subject of a recent column in American Scientist and a brief note here on bit-player, has won the 2008 EATCS Award of the European Association for Theoretical Computer Science. In addition to the work on holographic algorithms, the EATCS cites Valiant’s contributions of computational learning […]
Ages ago (in blog years) I mentioned some algorithmic ideas for getting passengers aboard airplanes faster, based on a 2005 paper by Steven Skiena and others. Since then, the queue at the departure gate has only gotten longer. Now another preprint on the same theme has landed in the arXiv. This one is by Jason […]