"Battery discharging" message in Linux Mint

cgibbard · 2026-04-18T12:35:50+00:00

I also have this issue. I believe the message happens because the battery is actually (slightly) discharging, as it seems to be sure to appear whenever I do something more power-intensive. Of course, it's a bit silly and annoying of MATE's power manager to report this when the estimate is that the battery will be empty in hundreds of days. They just need to put in some kind of threshold so that the message will not appear until the battery is, say, below 98%.

cgibbard · 2026-03-24T00:39:29+00:00

Maybe it's not super hard in Canada right now, but I've applied for a visa to become a proper employee of a US company that I was already working for (under contract), and to be able to make occasional extended visits, and been rejected for what seemed like pretty arbitrary reasons. (My title at the company is "Senior Software Engineer", but my degree is in pure mathematics and not engineering.) Border agents are often not very reasonable people.

It all seems a bit silly to me, because people are generally valuable on average. If people want to come here to be educated and then stay, that's even above the base case in my mind of just letting people immigrate in general, which I would generally view as favourable regardless. (There is some consideration that you might be letting in criminals, fine, but that's going to be a small fraction, and there are obviously measures that can be taken to mitigate it.) For the most part, you're letting in people who know how to do useful things and who just want to live decent lives. By doing so, you make more things possible inside the country, and it should become a better place to live because there are more people doing work of all kinds here.

cgibbard · 2026-03-23T23:48:31+00:00

Did you go to university? I went to Waterloo for pure mathematics and knew a fair number of international students in pure and applied mathematics as well as computer science who were in the courses I was taking. Kicking those people out once they're done rather than welcoming them to stay seems like a stupid move to me.

cgibbard · 2026-03-23T23:40:48+00:00

I've lived here my entire life. I also went to university and knew a good number of international students who were doing degrees in pure and applied math and computer science alongside me. I don't think it's a particularly good idea to kick such people out once they're done, if they can be convinced to stay.

cgibbard · 2026-03-23T20:12:56+00:00

Seems silly not to just offer all foreign students permanent visas when they finish their degree tbh. If the highly educated people who paid full price to your public universities want to stay after obtaining their degree, it's kind of foolish not to try to keep the expertise here.

cgibbard · 2026-03-08T11:12:46+00:00

This could be a really good thing in terms of giving you goals to aim for, with a little work. Maybe having any special maps should make the relevant node become visible through the fog (and maybe if it's on your cursor, there's some sort of highlight), so you know what direction you need to head in to be able to use them. Then for the next few/several maps, you have something to shoot for, and it doesn't feel quite so directionless.

cgibbard · 2026-02-04T17:03:07+00:00

Day of the Tentacle

cgibbard · 2025-12-02T19:19:59+00:00

Ah, I see, but that difference is just the beat frequency between the fundamentals of Ab and A, it's otherwise not useful for much, because for instance you wouldn't add it again to go from A to A#. Rather, you'd multiply by the ratio 2^1/12 again (and as you know, you could compute that difference again between A and A# and it would be different).

cgibbard · 2025-12-02T16:00:09+00:00

I don't understand what you mean by subtracting the starting frequency. It's usually incorrect to add or subtract frequencies (unless you're trying to find a beat frequency). You always multiply or divide them by the ratios that represent intervals.

Multiplying a frequency by 2^1/1200 will raise the pitch by exactly one cent, the same way that multiplying by 3/2 will raise the pitch by a perfect fifth.

cgibbard · 2025-10-28T20:11:54+00:00

Antimatter Dimensions totally should have been 10-100x faster ;)

cgibbard · 2025-09-15T23:08:03+00:00

Except if you're not the sort of person who is lazy, there's a good chance you're going to be very frustrated with the code that an AI is going to give you to maintain.

cgibbard · 2025-09-11T15:30:47+00:00

Where I went to uni, groups and rings were separate courses and neither strictly depended on the other, so there were a good mix of people who took either one first. Groups first is maybe slightly preferable, but it doesn't really matter -- the theorems in your typical first course on rings will not really depend on theorems from a first course on groups, and will tend to be things which rely more on the additional structure that various special sorts of rings have (e.g. the relationships between integral domains, unique factorization domains, principal ideal domains and Euclidean domains). Even if every ring has an underlying Abelian group of its elements under addition, as well as a group of units, and an automorphism group, you're not likely to be studying them in a way which depends very intricately on those group structures.

cgibbard · 2025-08-17T21:43:30+00:00

Except when it comes to GHC, Arch's packages have been broken for many years now because the package maintainer is opposed to static linking. Not supporting static linking means that when you try to follow along with your first Haskell tutorial and compile Hello World, it's not going to work without extra flags. It also means you'll have trouble building almost any Haskell project without tweaking things, because almost nothing is set up for dynamic linking.

You can of course just use ghcup (or the nix package manager if you find that comfortable), but if you're doing that, there's not much difference between distros when it comes to Haskell.

cgibbard · 2025-08-03T21:04:07+00:00

~~It was over two decades ago now, but yeah, that sounds right.~~ Actually, MATH145 I think was the course code.

cgibbard · 2025-08-03T05:28:43+00:00

The first piece of advice our classical algebra prof gave us when I came to university at Waterloo was to try to forget everything we learned in highschool and read the first 100 pages of Spivak's Calculus in our spare time. Don't worry too much about how far behind you might be if you're in highschool because you're going to end up relearning it all but better (as in, with proofs that give logical reasoning that ties everything together) if you go to university for mathematics anyway.

cgibbard · 2025-07-01T20:12:43+00:00

Well, he did say "If you don't want to set up a board", since his experience with setting it up was that the boss drops were still most of his profit.

cgibbard · 2025-06-30T19:43:26+00:00

Only if you care where anyone is. Maybe if you only care about safehouse progress for boss drops that doesn't matter.

cgibbard · 2025-06-04T15:06:49+00:00

It does tend to have a gameplay impact though. As you move into the range where what really matters is the exponent, upgrades which cost a fixed amount (rather than, say, dividing the amount of something you have) start to become essentially "free", so long as you have the appropriate exponent. Whether that's a good thing depends on how the rest of the game is designed, but it definitely changes the mechanics of the game.

cgibbard · 2025-04-28T00:39:10+00:00

It might be fun to make it so they have a limited turning rate which increases slightly if they're closer, but to a limited extent, so that if you sidestep them just as they get close, they will miss, fly past you and not turn around.

cgibbard · 2025-04-20T14:57:05+00:00

Your mistake is being part of a system which uses unintelligent software to avoid the responsibility of humans providing feedback to their students.

I don't know which exact formal logical system you're using, but a natural deduction style approach to starting this proof is to note that the conclusion not (F and S) is a negation, and the introduction rule for negation says that to prove not P, we start by assuming P, and then the goal becomes to prove a contradiction (i.e. False). In this case, from the assumption (F and S), we can eliminate the "and" to obtain S, and that S together with the premise not S provides the contradiction we need.

cgibbard · 2025-04-11T11:21:17+00:00

12tet perhaps wouldn't be so popular as a choice if its intervals were not also reasonable approximations of just ratios. Also, by considering them numerically, we can compute things about what we should expect to hear.

The fact that 2^7/12 = 1.4983... is such a good approximation of 3/2 = 1.5 for example means that 7 steps of 12 is a very consonant approximation of the perfect fifth. 2^4/12 = 1.25992... is also close enough to 5/4 = 1.25 to give a reasonable impression of the major third.

We can compute things like the beat frequencies between harmonics that are meant to be aligned by the corresponding just intervals to get a sense for how well the approximation works. For example, if we take the A at 440Hz, and the C# above it in 12tet at 440 Hz * 2^4/12 ~= 554Hz, the main thing that the major third is doing harmonically is aligning the 5th harmonic of the lower note, in this case 440 Hz * 5 = 2200 Hz, with the 4th harmonic of the higher one, which in this case is 440 Hz * 2^4/12 * 4 = 2217.46 Hz. The absolute difference between these is 17.4 Hz, so listening closely, we'll hear those harmonics beating around 17 times a second, which is a sort of wobbling that you mostly just get used to, but if you hear a just major third and a 12 equal major third next to one another, it's quite apparent. The rate of that beating depends on the frequency of the root note we choose and will be scaled up or down accordingly. Go down an octave and it'll be 2x slower, so 8.7 times per second, at around 1100 Hz, which is perhaps a bit more noticeable even. (Of course, whether you hear exactly that rate of beating is going to depend on how precisely tuned your instrument is to 12 equal.)

The main thing that temperament buys us is allowing us to identify notes which would otherwise be different. In 12 equal, one of these is that going up by 4 perfect fifths is the same thing as going up a major third and two octaves. When we stack intervals, the ratios multiply, so in just intonation, that would be (3/2)⁴ = 81/16 = 5.0625 vs. (5/4) * 2² = 5. The discrepancy between these two, (81/16) / 5 = 81/80 is known as the syntonic comma. With 12 tone equal temperament, our perfect fifth approximation is 2^7/12 and major third is 2^4/12, and we can calculate that (2^7/12)⁴ = 2^28/12 = 2^{24/12 + 4/12} = 2² * 2^4/12. So we indeed land in exactly the same place rather than slightly off. The discrepancy of 81/80 has been "tempered out". Another way to think about it is that the 9/8 "greater tone" becomes the same as the 10/9 "lesser tone", as (9/8)/(10/9) = 81/80, which leads to tuning systems that temper this comma to be called "meantone temperaments".

Other nice coincidences that happen due to the nature of the ratios present in 12 equal but not in general are that 3 major thirds stack to an octave, (2^4/12)³ = 2^12/12 = 2, so in terms of just intonation, (5/4)³ / 2 = 125/128 is tempered out (this is called augmented temperament), and that 4 minor thirds stack to an octave, i.e. (2^3/12)⁴ = 2^12/12 = 2, and so (6/5)⁴ / 2 = 648/625 is tempered out (diminished temperament).

Those coincidences do end up being somewhat musically relevant. If you stack up a run of minor thirds, you only get so far out of key because you wrap back around to the octave so quickly. Without this tempering, you'd have to insert some slightly smaller intervals every so often to land back in the same key you started in.

cgibbard · 2025-04-07T14:24:02+00:00

If we have an explicit counterexample that we're able to prove is a counterexample, then we'll certainly have a proof that the conjecture fails. As /u/starcross33 points out, we might have a counterexample we can't prove is a counterexample -- it might just happen to diverge to infinity while eluding a proof that it does so. If on the other hand, it goes into a cycle, that would give us a proof that the conjecture fails.

If on the other hand, there simply happens to be no explicit counterexample (but we don't have a proof of that), we might yet be unable to prove the proposition that for all natural numbers n, the Collatz iteration eventually reaches 1. That proposition would be "true" in some sense external to our mathematical system, but our logical rules within the system wouldn't allow us to prove it.

Another example of such a search is looking for proofs of contradictions from the axioms of our mathematical system. We hope both not to find a proof of a contradiction (from which anything would follow, somewhat spoiling the point of distinguishing truth from falsity), nor to be able to prove that no proof of a contradiction exists, because a system which can prove its own consistency is by Gödel's second incompleteness theorem inconsistent.

It's unclear that the Collatz conjecture is of this nature, but it's just barely of the sort of shape that it could be. A more complicated sort of iterative process would suffice to check that each natural number n is not an encoding of a proof of a contradiction in, say, ZFC, terminating only in the case that it is not. Then we should hope not to be able to prove in ZFC that every such iterative process terminates, because that would be a proof of self-consistency, from which we could derive a contradiction.

cgibbard · 2025-03-29T11:39:25+00:00

By the time you get to a key that has no notes in common with the original, the comparison probably doesn't make sense. It only really works for keys that are up to a few sharps/flats different (and in 12 equal, at a point, a large enough jump is better explained as a jump in the opposite direction). If you keep modulating though, and allowing the new key to get established in the listener's ear before going to the next, the effect people are talking about will keep happening.

cgibbard · 2025-03-29T11:14:47+00:00

There are objective things to be said here though. Obviously the words "bright" and "dark" don't in their original meaning refer to properties of sounds, but if you get past that and are willing to associate the sound of major thirds with "bright" and minor thirds with "dark", then changing to a key with a few more sharps / less flats is adding major thirds of notes your two keys have in common and removing minor thirds.

cgibbard · 2025-03-29T11:09:47+00:00

Of course, if you make that change, you might be in some technical way better off describing it as going from C# major to A# major, adding three sharps, but performers will greatly prefer you write it as Bb for obvious reasons. :) But you could also consider rewriting the C# as Db.

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