|The Universe of Discourse|
12 recent entries
In this section:
Sat, 14 Feb 2009
I have an idea that I might inaugurate a new section of the blog, called "junkheap", where unfinished articles would appear after aging in the cellar for three years, regardless what sort of crappy condition they are in.Some of the stuff in the cellar is in pretty good shape. Some is really trash. I don't want to publish any of it on the main blog, for various reasons; if I did, I would have already. But some of it might have some interest for someone, or I wouldn't be revisiting it at all.
Here's a summary of the cellared items from February-April 2006, with the reasons why each was abandoned:
I invite your suggestions for what to do with this stuff. Mailing list? Post brief descriptions in the blog and let people request them by mail? Post them on a wiki and let people hack on them? Stop pretending that my every passing thought is so fascinating that even my failures are worth reading?
The last one is the default, and I apologize for taking up your valuable time with this nonsense.
Sat, 27 Oct 2007
Where's that blog?
I said a while back that I would try to publish more regularly, and not wait until every article was perfect. But I don't want to publish the unfinished articles yet. So I thought instead I'd publish a short summary of what I've been thinking about lately.
I hope to get at least one or two of these done by the end of the month.
Simplified PokerI recently played a computer poker game that uses a 24-card deck, with only the nine through ace of each suit. This changes the game drastically. For example, a flush is less likely than a four of a kind. (The game uses the standard hand rankings anyway.) It is very easy to compute optimal strategies for this game, because there are so few possible hands (42,504) that you can brute-force all the calculations with a computer.
This got me thinking again of something I started writing up last year and never finished: The game of "Simplified Poker", which was an attempt to do for Poker what the λ-calculus does for computation: the simplest possible model that nevertheless captures all the essential features of the original. Simplified Poker is played with an infinite deck in which half the cards are kings and half are jacks. Each hand contains only two cards. Nevertheless, bluffing is still possible.
The Annoying Boxes PuzzleThis is a logic puzzle in which you deduce which box contains the treasure, but with a twist. I thought it up many years ago, and then in the course of trying to write up an explanation about five years ago, I consulted Raymond Smullyan's book What is the Name of This Book? in order to get a citation to prove a certain fact about the form that such puzzles usually take. In doing so, I discovered that Smullyan actually presented the annoying boxes puzzle (in slightly different form) in that book!
It's primarily waiting for me to take a photograph to accompany the puzzle.
Undefined behaviorI have a pretty interesting article on the concept of "undefined behavior", which is a big deal in the C world, but which means something rather different, and is much less important, in Perl.
[ Addendum 20071029: This is ready now. ]
TootleMy daughter Iris has become interested in the book Tootle, by Gertrude Crampton, which is the third-best-selling hardback children's book of all time. A few years back I wrote some brief literary criticism of Tootle, which I included when I wrote the Wikipedia article about the book. This criticism was quite rightly deleted later on, as uncited original research. It needs a new home, and that home is obviously here.
Periodicity without Fourier SeriesSuppose I have tabulated the number of blog posts I made every day for two years. I want to find if there is any discernible periodicity to this data. Do I tend to post in 26-day cycles, for example?
One way to do this is to take the Fourier transform of the data. For various reasons, I don't like this technique, and I'm trying to invent something new. I think I have what I want, although it took several tries to find it. Unfortunately, the blog posting data shows no periodicity whatsoever.
Emacs and auto-mode-alistThe elisp code I've been using for the past fifteen years to set the default mode for Perl editing in Emacs broke last week. My search for a replacement turned up some very bizarre advice on IRC.
Van der Waerden's problemAlso still pending is the rest of my van der Waerden problem series. I have written about four programs so far, and I have two to go.
Sun, 05 Aug 2007
Sub-blogs and the math sub-blog
If you really do want just the math articles for some reason, you can subscribe to the feeds at http://blog.plover.com/math/index.rss or http://blog.plover.com/math/index.atom. I've been generating these sub-feed files since the blog began, and I know nobody uses them. But perhaps someone would like to.
Similarly, there are sub-feeds for other subsections of the blog, for example "physics". Most of these topic areas receive many fewer updates than does the "math" section:
Personally I feel that the eclecticism of the blog is one of its attractions, and I gather that a lot of other people do too, but perhaps not everyone agrees.
Mon, 30 Apr 2007
Woodrow Wilson on bloggers
Uncompromising thought is the luxury of the closeted recluse.
(Part of a speech at the University of Tennessee in 17 June, 1890).
Bloggers beware; Woodrow Wilson has your number.
Sun, 18 Feb 2007
ALT attributes in formula image elements
Today I fixed the plugin to leave the original TeX source code in the ALT attribute of the IMG tag. I should have done this in the first place.
If any people with vision impairments read my blog and have suggestions about how I could make it more accesible, I would be very grateful to hear them.
Mon, 08 Jan 2007
State of the Blog 2006
OutputNot counting this article, I posted 161 articles this year, totalling about 172,000 words, which I think is not a bad output. About 1/4 of this output was about mathematics.
The longest article was the one about finite extension fields of Z2; the shortest was the MadHatterDay commemorative. Other long articles included some math ones (metric spaces, the Pólya-Burnside theorem) and some non-math ones (how Forbes magazine made a list of the top 20 tools and omitted the hammer, do aliens feel disgust?).
I drew, generated, or appropriated about 300 pictures, diagrams, and other illustrations, plus 66 mathematical formulas. This does not count the 50 pictures of books that I included, but it does include 108 little colored squares for the article on the Pólya-Burnside counting lemma.
FinancialI incurred the costs of Dreamhosting (see below). But these costs are offset because I am also using the DreamHost as a remote backup for files. So it has some non-blog value, and will also result in a tax deduction.
None of the book links earned me any money from kickbacks. However, the blog did generate some income. When Aaron Swartz struck oil, he offered to give away money to web sites that needed it. Mine didn't need it, but a little later he published a list of web sites he'd given money to, and I decided that I was at least as deserving as some of them. So I stuck a "donate" button on my blog and invited Aaron to use it. He did. Thanks, Aaron!
I now invite you to use that button yourself. Here are two versions that both do the same thing:
My MacArthur Fellowship check has apparently been held up in the mail.
PopularityThe most popular article was certainly the one on Design Patterns of 1972. I had been thinking this one over for years, and I was glad it attracted as much attention as it did. Ralph Johnson (author of the Design Patterns book) responded to it, and I learned that Design Patterns is not the book that Johnson thought it was. Gosh, I'm glad I didn't write that book.
The followup to the Design Patterns article was very popular also. Other popular articles were on risk, the envelope paradox, the invention of the = sign, and ten science questions every high school graduate should be able to answer.
My own personal favorites are the articles about alien disgust, the manufacture of round objects, and what makes π so peculiar. In that last one, I think I was skating on the thin edge of crackpotism.
The article about Forbes' tool list was mentioned in The New York Times.
The blog attracted around five hundred email messages, most of which were intelligent and thoughtful, and most of which I answered. But my favorite email message was from the guy who tried to convince me that rock salt melts snow because it contains radioactive potassium.
System administrationI moved the blog twice. It originally resided on www.plover.com, which is in my house. I had serious network problems in July and August, Verizon's little annual gift to me. When I realized that the blog was be much more popular than I expected, and that I wanted it to be reliably available, I moved it to newbabe.pobox.com, which I'd had an account on for years but had never really used. This account was withdrawn a few months later, so I rented space at Dreamhost, called blog.plover.com, and moved it there. I expect it will stay at Dreamhost for quite a while.
Moving the blog has probably cost me a lot of readers. I know from the logs that many of them have not moved from newbabe to Dreamhost. Traffic on the new site just after the move was about 25% lower than on the old site just before the move. Oh well.
If the blog hadn't moved so many times, it would be listed by Technorati as one of the top ten blogs on math and science, and one of the top few thousand overall. As it is, the incoming links (which are what Technorati uses to judge blog importance) are scattered across three different sites, so it appears to be three semi-popular blogs rather than one very popular blog. This would bother me, if Technorati rankings weren't so utterly meaningless.
PolicyI made a couple of vows when I started the blog. A number of years ago on my use.perl.org journal I complained extensively about some people I worked with. They deserved everything I said, but the remarks caused me a lot of trouble and soured me on blogs for many years. When I started this blog, I vowed that I wouldn't insult anyone personally, unless perhaps they were already dead and couldn't object. Some people have no trouble with this, but for someone like me, who is a seething cauldron of bile, it required a conscious effort.
I think I've upheld this vow pretty well, and although there have been occasions on which I've called people knuckleheaded assholes, it has always been either a large group (like Biblical literalists) or people who were dead (like this pinhead) or both.
Another vow I made was that I wasn't going to include any tedious personal crap, like what music I was listening to, or whether the grocery store was out of Count Chocula this week. I think I did okay on that score. There are plenty of bloggers who will tell you about the fight they had with their girlfriend last night, but very few that will analyze abbreviations in Medieval Latin. So I have the Medieval Latin abbreviations audience pretty much to myself. I am a bit surprised at how thoroughly I seem to have communicated my inner life, in spite of having left out any mention of Count Chocula. This is a blog of what I've thought, not what I've done.
What I didn't post this yearMy blog directory contains 55 unpublished articles, totalling 39,500 words, in various states of incompleteness; compare this with the 161 articles I did complete.
The longest of these unpublished articles was written some time after my article on the envelope paradox hit the front page of Reddit. Most of the Reddit comments were astoundingly obtuse. There were about nine responses of the type "That's cute, but the fallacy is...", each one proposing a different fallacy. All of the proposed fallacies were completely wrong; most of them were obviously wrong. (There is no fallacy; the argument is correct.) I decided against posting this rebuttal article for several reasons:
The article about metric spaces was supposed to be one of a three-part series, which I still hope to finish eventually. I made several attempts to write another part in this series, about the real numbers and why we have them at all. This requires explanation, because the reals are mathematically and philosophically quite artificial and problematic. (It took me a lot of thought to convince myself that they were mathematically inevitable, and that the aliens would have them too, but that is another article.) The three or four drafts I wrote on this topic total about 2,100 words, but I still haven't quite got it where I want it, so it will have to wait.
I wrote 2,000 words about oddities in my brain, what it's good at and what not, and put it on the shelf because I decided it was too self-absorbed. I wrote a complete "frequently-asked questions" post which answered the (single) question "Why don't you allow comments?" and then suppressed it because I was afraid it was too self-absorbed. Then I reread it a few months later and thought it was really funny, and almost relented. Then I read it again the next month and decided it was better to keep it suppressed. I'm not indecisive; I'm just very deliberate.
I finished a 2,000-word article about how to derive the formulas for least-squares linear regression and put it on the shelf because I decided that it was boring. I finished a 1,300-word article about quasiquotation in Lisp and put it on the shelf because I decided it was boring. (Here's the payoff from the quasiquotation article: John McCarthy, the inventor of Lisp, took both the concept and the name directly from W.V.O. Quine, who invented it in 1940.)
Had I been writing this blog in 2005, there would have been a bunch of articles about Sir Thomas Browne, but I was pretty much done with him by the time I started the blog. (I'm sure I will return someday.) There would have been a bunch of articles about John Wilkins's book on the Philosophical Language, and some on his book about cryptography. (The Philosophical Language crept in a bit anyway.) There would have been an article about Charles Dickens's book Great Expectations, which I finished reading about a year and a half ago.
An article about A Christmas Carol is in the works, but I seem to have missed the seasonal window on that one, so perhaps I'll save it for next December. I wrote an article about how to calculate the length of the day, and writing a computer progam to tell time by the old Greek system, which divides the daytime into twelve equal hours and the nighttime into twelve equal hours, so that the night hours are longer than the day ones in the winter, and shorter in the summer. But I missed the target date (the solstice) for that one, so it'll have to wait until at least the next solstice. I wrote part of an article about Hangeul (the Korean alphabet), planning to publish it on Hangeul Day (the Koreans have a national holiday celebrating Hangeul) but I couldn't find the quotations I wanted from 1445, so I put it on the shelf. This week I'm reading Gari Ledyard's doctoral thesis, The Korean Language Reform of 1446, so I may acquire more information about that and be able to finish the article. (I highly recommend the Ledyard thing; it's really well-written.) I recently wrote about 1,000 words about Vernor Vinge's new novel Rainbows End, but that's not finished yet.
A followup to the article about why you don't have one ear in the middle of your face is in progress. It's delayed by two things: first, I made a giant mistake in the original article, and I need to correct it, but that means I have to figure out what the mistake is and how to correct it. And second, I have to follow up on a number of fascinating references about directional olfaction.
Sometimes these followups eventually arrive,as the one about ssh-agent did, and sometimes they stall. A followup to my early article about the nature of transparency, about the behavior of light, and the misconception of "the speed of light in glass", ran out of steam after a page when I realized that my understanding of light was so poor that I would inevitably make several gross errors of fact if I finished it.
I spent a lot of the summer reading books about inconsistent mathematics, including Graham Priest's book In Contradiction, but for some reason no blog articles came of it. Well, not exactly. What has come out is an unfinished 1,230-word article against the idea that mathematics is properly understood as being about formal systems, an unfinished 1,320-word article about the ubiquity of the Grelling-Nelson paradox, an unfinished 1,110-word article about the "recursion theorem" of computer science, and an unfinished 1,460-word article about paraconsistent logic and the liar paradox.
I have an idea that I might inaugurate a new section of the blog, called "junkheap", where unfinished articles would appear after aging in the cellar for three years, regardless what sort of crappy condition they are in. Now that the blog is a year old, planning something two years out doesn't seem too weird.
I also have an ideas file with a couple hundred notes for future articles, in case I find myself with time to write but can't think of a topic. Har.
SurprisesI got a number of unpredictable surprises when I started the blog. One was that I wasn't really aware of LiveJournal, and its "friends" pages. I found it really weird to see my equation-filled articles on subvocal reading and Baroque scientific literature appearing on these pages, sandwiched between posts about Count Chocula from people named "Taldin the Blue Unicorn". Okay, whatever.
I was not expecting that so many of my articles would take the form "ABCDEFG. But none of this is really germane to the real point of this article, which is ... HIJKLMN." But the more articles I write in this style, the more comfortable I am with it. Perhaps in a hundred years graduate students will refer to an essay of this type, with two loosely-coupled sections of approximately the same length, linked by an apologetic phrase, as "Dominus-style".
Wrong wrong wrong!I do not have a count of the number of mistakes and errors I made that I corrected in later articles, although I wish I did. Nor do I have a count of the number of mistakes that I did not correct.
However, I do know that the phrase "I don't know" (and variations, like "did not know") appears 67 times, in 44 of the 161 articles. I would like to think that this is one of the things that will set my blog apart from others, and I hope to improve these numbers in the coming years.
ThanksThanks to all my readers for their interest and close attention, and for making my blog a speedy success.
Tue, 28 Nov 2006
My first thought was, of course, to use an octopus, but I immediately rejected this idea since I didn't think I would be able to draw a recognizable octopus in 16×16 pixels. Neil Kandalgaonkar was braver than I was: .
However, the concept I decided to go with was suggested by David Eppstein, who provided this attractive interpretation: . To explain this, I need to explain my domain name, which I haven't done here before.
For nine years I was an independent consultant, working under the name Plover Systems. Why Plover? Many people assume that it is an abbreviation for "Perl lover"; this is not the case. The plover domain predates my involvement with Perl. (Some people have also interpreted it as "piss lover", a veiled statement of a fetishistic attraction to urination. It is not.)
A plover is a small bird. Typically, they make their nests on the seashore. The Egyptian plover is the little bird that is reputed to snatch food scraps from between the teeth of the crocodile. The American golden plover migrates all the way from Alaska to South America, and sometimes across the ocean to Europe.
Immediately prior to my becoming an independent consultant and setting up Plover Systems and the plover.com domain, I was employed as the senior systems engineer for Pathfinder, the Time Warner web site. I did not like this job very much. After I quit, I joked that my company had grown too big, so I downsized most of the management and employees, divested the magazine business, and cut the organization's mission back to core competences. Time Warner, the subsidiary I spun off to publish the magazines, was very large. I named my new, lean, trim company "Plover" because the plover is small and agile.
There is another reason for "Plover". For about thirty years, I have been a devoted fan of the old computer game Adventure. When time came to choose a domain name, I wanted to choose something with an Adventure connection. Here the obvious choices are xyzzy, which was already taken, and plugh, which is ugly. Both of these are magic words which, uttered at the correct spot, will teleport the player to another location. The game has a third such magic word, which is "plover"; from the right place, it transports the player to the "Plover room":
You're in a small chamber lit by an eerie green light. An extremely narrow tunnel exits to the west. A dark corridor leads NE.This room, with its green light and narrow tunnel, is depicted in David Eppstein's icon.
The Plover room is so-called because it contains "an emerald the size of a plover's egg". A plover's egg is not very big, as eggs go, because the plover is not a very large bird, as birds go. But an emerald the size of a plover's egg is enormous, as emeralds go. The description is a reference to an off-color joke that was current in the early 1970's when Adventure was written: a teenage girl, upon hearing that the human testicle is the size of a plover's egg, remarks "Oh, so that's how big a plover's egg is." I think this was somewhat more risqué in 1974 than it is today.
For his contribution, M. Eppstein has won a free two-year subscription to The Universe of Discourse. Neil Kandalgaonkar gets the runner-up prize of two free six-month subscriptions, to run concurrently. Thank you both!
Mon, 20 Nov 2006
I have not had any good ideas. So I am asking LazyNet.
The best suggestion will win a free one-year subscription to The Universe of Discourse blog. If the winner supplies an icon that I can actually use, the prize will be increased to a free two-year subscription.
[ Addendum 20061120: David Eppstein responded immediately with , which I will explain in a future article that summarizes the suggestions. M. Eppstein's suggestion is good enough that I am comfortable installing it right away. But don't let that stop you from coming up with your own suggestion. ]
[ Addendum 20061120: Neil Kandalgaonkar has contributed . Thank you, Neil! ]