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The Universe of Discourse

The Universe of...
A complex bug with a ⸢simple⸣ fix Last month I did a fairly complex piece of systems programming that worked surprisingly well. But...
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6 months ago
Last month I did a fairly complex piece of systems programming that worked surprisingly well. But it had one big bug that took me a day to track down. One reason I find the bug interesting is that it exemplifies the sort of challenges that come up in systems programming. The...
The Universe of...
Another corner of Pennsylvania [ Previously: [1] [2] [3] ] A couple of years back I wrote: I live in southeastern Pennsylvania, so...
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6 months ago
[ Previously: [1] [2] [3] ] A couple of years back I wrote: I live in southeastern Pennsylvania, so the Pennsylvania-New Jersey-Delaware triple point must be somewhere nearby. I sat up and got my phone so I could look at the map, and felt foolish. As you can see, the triple...
The Universe of...
Loki the comedian Toph and I were discussing the story of Loki and Skaði, one of my favorites. (Previously.) The...
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Toph and I were discussing the story of Loki and Skaði, one of my favorites. (Previously.) The Æsir have killed Skaði's father, and owe her compensation. She has been sad since her father died, she says, and demands that the Æsir make her laugh. Loki rubs his hands together...
The Universe of...
Everyday examples of morphisms with one-sided inverses Like almost everyone except Alexander Grothendieck, I understand things better with examples. For...
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Like almost everyone except Alexander Grothendieck, I understand things better with examples. For instance, how do you explain that $$(f\circ g)^{-1} = g^{-1} \circ f^{-1}?$$ Oh, that's easy. Let be putting on your shoes and be taking off your shoes. And let be putting...
The Universe of...
Dancing bread Marnanel Thurman reported the following item that they found in an 1875 book titled How to Entertain...
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Marnanel Thurman reported the following item that they found in an 1875 book titled How to Entertain a Social Party: To Make a Loaf of Bread Dance on the Table. — Having a quill filled with quicksilver and stopped close, you secretly thrust it into a hot roll or loaf, which...
The Universe of...
Look at what they tried to take from us When I was a kid, the Beatles’ seminal 1966 album Revolver was 20% shorter. The original release...
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When I was a kid, the Beatles’ seminal 1966 album Revolver was 20% shorter. The original release was not a long album: 14 tracks, totaling 34:45. But the version I grew up with had 11 tracks, totaling only 27:31. Three tracks, all by Lennon, were omitted by Capitol from the...
The Universe of...
My reply to the people who want to designate my neighborhood a "historic district" Last week I received a widely circulated email that began: With tall apartment buildings being...
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Last week I received a widely circulated email that began: With tall apartment buildings being erected all around, we feel it is ever more important to preserve our community. I sent this reply. I have been a Spruce Hill homeowner for 16 years. I had to miss the June 26...
The Universe of...
Poor Richard's Almanack Benjamin Franklin wrote and published Poor Richard's Almanack annually from 1732 to 1758. Paper...
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Benjamin Franklin wrote and published Poor Richard's Almanack annually from 1732 to 1758. Paper was expensive and printing difficult and time-consuming. The type would be inked, the sheet of paper laid on the press, the apprentices would press the sheet, by turning a big screw....
The Universe of...
I DON'T KNOW If you're an annoying know-it-all like me, I suggest that you try playing the following game when...
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If you're an annoying know-it-all like me, I suggest that you try playing the following game when you attend a conference or a user group meetup or even a work meeting. The game is: If someone asks you a question, and you say “I don't know”, you score a point. That's it. ...
The Universe of...
XKCD game theory question (Source: XKCD “Exam numbers”.) This post is about the bottom center panel, “Game Theory final...
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(Source: XKCD “Exam numbers”.) This post is about the bottom center panel, “Game Theory final exam”. I don't know much about game theory and I haven't seen any other discussion of this question. But I have a strategy I think is plausible and I'm somewhat pleased with. (I assume...
The Universe of...
A triviality about numbers that look like abbc Looking at license plates the other day I noticed that if you have a four-digit number with digits...
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Looking at license plates the other day I noticed that if you have a four-digit number with digits , and , then will always be a multiple of . For example, and . Mathematically this is uninteresting. The proof is completely trivial. (Such a number is simply , and .) But I...
The Universe of...
Stuff I wanted to say to the historic district people but didn't [ Thanks to John Wiersba for noticing that I forgot to publish this. ] A few weeks ago I wrote a...
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[ Thanks to John Wiersba for noticing that I forgot to publish this. ] A few weeks ago I wrote a letter to my neighbors about why I thought it was a bad idea to oppose building more housing in our neighborhood. I didn't write this paragraph: In the past it has often happened that...
The Universe of...
David McShane's mural with 18 Franks, revealed Yesterday I offered Gentle Readers a chance to identify the 18 famous Franks in David McShane's...
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Yesterday I offered Gentle Readers a chance to identify the 18 famous Franks in David McShane's mural. Benjamin Franklin Frankie Avalon Detail of ornament from the Pennsylvania Academy of the Fine Arts building, designed by architect Frank Furness A frankfurter Aretha...
The Universe of...
Just ANSWER THE QUESTION Here's a Math SE pathology that bugs me. OP will ask "I'm trying to prove that groups and are...
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Here's a Math SE pathology that bugs me. OP will ask "I'm trying to prove that groups and are isomorphic, I constructed this bijection but I see that it's not a homomorphism. Is it sufficient, or do I need to find a bijective homomorphism?" And respondent will reply in the...
The Universe of...
Think speak, now speak! Katara is now in her sixth semester in college and can speak Mandarin. I am so proud! For class she...
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Katara is now in her sixth semester in college and can speak Mandarin. I am so proud! For class she recently wrote a talk (in Mandarin) about Hua Guofeng, the often overlooked second chairman of the Chinese Communist Party. She videoed herself giving the talk, and posted it to...
The Universe of...
Polish Spam Content warning: mass killing of farmed animals Today I complained that my email provider had...
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Content warning: mass killing of farmed animals Today I complained that my email provider had delivered a spam message to me that was in Polish. I understand that spam can be hard to identify, but Polish isn't, I don't know Polish, and any message sent to me in Polish can be...
The Universe of...
Surnames from nicknames nobody has any more English has a pattern of common patronymic names. For example, "John Peters" and "John Peterson"...
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English has a pattern of common patronymic names. For example, "John Peters" and "John Peterson" are someone whose father was named "Peter". ("Peters" should be understood as "Peter's".) Similarly we have John Williams and John Williamson, John Roberts and John Robertson, John...
The Universe of...
Claude helps me find more presidential emoji A couple of years back I tried to make a list of emoji representing the U.S. presidents. Many of...
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A couple of years back I tried to make a list of emoji representing the U.S. presidents. Many of them were fun and easy, or at least amused me. But for some I was stumped. What emoji represents Zachary Taylor? I've been playing around with Anthropic's LLM “Claude” for a while,...
The Universe of...
Leopards, faces, etc. I expect we in the United States are about to see a wave of domestic terrorism unprecendented since...
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I expect we in the United States are about to see a wave of domestic terrorism unprecendented since the 1870s. In the wake of the Civil War, white Southerners used systematic terrorism to continue white supremacy. If a black person became too prosperous, masked thugs would come...
The Universe of...
David McShane's mural with 18 Franks Since the demolition of Harriet Tubman, this has been my favorite mural in Philadelphia. It's by...
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Since the demolition of Harriet Tubman, this has been my favorite mural in Philadelphia. It's by Philadelphia muralist David McShane. The mural is outside an infamous windowless bar called Dirty Frank's. I like to say that Oscar's Tavern on Sansom is Philadelphia's best...
The Universe of...
Genealogy of the House of Reuss A couple of years ago I lamented the difficulty I had in verifying what appeared to be a simple...
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A couple of years ago I lamented the difficulty I had in verifying what appeared to be a simple statement of fact: [Abdullah bin Abdul-Rahman] was the seventh son of the Emir of the Second Saudi State, Abdul Rahman bin Faisal. The essential problem is that Saudi princes have at...
The Universe of...
Just give the man the fish! Last week I complained about a Math SE pathology in which OP asks a simple question, and instead of...
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Last week I complained about a Math SE pathology in which OP asks a simple question, and instead of an answer gets an attempt at a socratic dialog. I ended by saying: I have been banging this drum for decades, but I will cut the scroll here. Expect a followup article. Seeing...
The Universe of...
Polish Spam Content warning: mass killing of farmed animals Today I complained that my email provider had...
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4 months ago
Content warning: mass killing of farmed animals Today I complained that my email provider had delivered a spam message to me that was in Polish. I understand that spam can be hard to identify, but Polish isn't, I don't know Polish, and any message sent to me in Polish can be...
The Universe of...
Claude and Merle Miller let me down Claude My relationship with Claude has its ups and downs, and I'm still trying to figure out what to...
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Claude My relationship with Claude has its ups and downs, and I'm still trying to figure out what to use it for and what not. It's great at rewriting my job application cover letters to sound less like an awkward nerd. Last week I was in the supermarket and decided to try asking...
The Universe of...
Reflector grids Around here, these metal things are commonly found on streetside utility poles, attached maybe a...
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Around here, these metal things are commonly found on streetside utility poles, attached maybe a meter off the ground. .image-group { display: flex; flex-direction: row; align-self: center; justify-content: center; gap: 4em; } .image-group .image { ...
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Jonathan Chait [ Content warning: angry, contemptuous ranting that accomplishes nothing. ] I didn't really know who...
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[ Content warning: angry, contemptuous ranting that accomplishes nothing. ] I didn't really know who Jonathan Chait was until last week when I unfortunately read this essay of his (from February 2016) on “Why Liberals Should Support a Trump Republican Nomination”. I've said a lot...
The Universe of...
Furniture Mecca [ Content warning: shitpost ] It's that time of year again! Furniture Mecca is having their...
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[ Content warning: shitpost ] It's that time of year again! Furniture Mecca is having their annual sale. This year the sale will run until Friday the 28th. At closing time on that day any remaining furniture will be hurriedly moved to the owner's other furniture store,...
The Universe of...
Hangeul sign-engraving machine Last summer I was privileged to visit the glorious Letterpress Museum in Paju Book City, where I...
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Last summer I was privileged to visit the glorious Letterpress Museum in Paju Book City, where I spent several hours and took a collection of photos that are probably not of interest to anyone but letterpress geeks, and perhaps not even to them. Looking back at the photos it's...
The Universe of...
Claude chokes on graph theory .bad { border: thin solid red; } Having had some pleasant surprises from Claude, I thought I'd...
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.bad { border: thin solid red; } Having had some pleasant surprises from Claude, I thought I'd see if it could do math. It couldn't. Apparently some LLMs can sometimes solve Math Olympiad problems, but Claude didn't come close. First I asked something simple as a...
The Universe of...
Baseball on the Moon We want to adapt baseball to be played on the moon. Is there any way to make it work? My first...
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We want to adapt baseball to be played on the moon. Is there any way to make it work? My first impression is: no, for several reasons. The pitched ball will go a little faster (no air resistance) but breaking balls are impossible (ditto). So the batter will find it easier to...
The Universe of...
The mathematical past is a foreign country A modern presentation of the Peano axioms looks like this: is a natural number If is a natural...
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A modern presentation of the Peano axioms looks like this: is a natural number If is a natural number, then so is the result of appending an to the beginning of Nothing else is a natural number This baldly states that zero is a natural number. I think this is a 20th-century...
The Universe of...
Does someone really have to do the dirty jobs? Doing the laundry used to be backbreaking toil. Haul the water, chop the wood, light the fire, heat...
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Doing the laundry used to be backbreaking toil. Haul the water, chop the wood, light the fire, heat the water, and now you are ready to begin the really tough part of the work. The old saying goes "Wash on Monday", because Monday is the day after your day of rest, and otherwise...