Vassil Nikolov | Васил Николов

Radio specialist;
mathematician;
interpreter;
software engineer;
and jack of other trades.

Name pronunciation: vah-SIL nih-KOH-lov
Meridian time (offset from zulu time): +01:33
Blog, posts in English, some of them bilingual: https://vnikolov-lines.blogspot.com/search/label/language%3AEnglish
Blog, all posts: https://vnikolov-lines.blogspot.com/

Public Key

npub1eucypjwfhjzyazlphtgqx508aqz90yg3yd2m5dp5uszafxxsxmxs6gfkvk

NIP-05 Address

[email protected]

Profile Code

nprofile1qqsv7vzqe8ymepzw30sm45qr28n7spzhjygjx4d6xs6wgpw5nrgrdngprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntkj2xuw

Publishing to

relay.momostr.pink

Author Public Key

npub1eucypjwfhjzyazlphtgqx508aqz90yg3yd2m5dp5uszafxxsxmxs6gfkvk

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Last Notes

2026-07-27 21:00:30 UTC

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What is left about this Scheme?
(Left as the opposite of right-hand-side, not as abandoned or gone.)
[@ramin_hal9001](https://fe.disroot.org/users/ramin_hal9001 )

2026-07-24 18:47:59 UTC

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This reminded me of public competitions between mathematicians several centuries ago (say, 16th century).
Mathematicians did not publish (some of) their achievements, so they would have problems to give their opponents at such competitions.
If I recall correctly, Cardano or somebody close to him famously did that.
@npub152p…3yjg @npub1nf4…nqe4

2026-07-24 05:47:00 UTC

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Off topic, is this the very same name as that of the Chinese political leader of the late 70s and early 80s?
@npub17w4…r3cf @npub1nf4…nqe4

2026-07-18 18:25:29 UTC

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Were you surprised that this average distance is a rational number?

2026-06-23 16:51:30 UTC

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I only wish I had experience with Plan 9.
I have used `rc', though.
(I have used `es', too, for that matter.)
@npub1fp0…54p5 @npub1lym…fqe3 @npub1gnu…0jmx

2026-06-07 07:52:53 UTC

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Nice picture!
Is this an M-1 rifle?
(Garrand?)
@npub1fp0…54p5

2026-05-28 17:55:30 UTC

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Thank you!
This reminded me—I know it isn't an analogy—of an algorithm for tree traversal that takes an auxiliary data structure as a parameter and does depth-first traversal given a stack (LIFO) and breadth-first with a queue (FIFO).
@npub1nf4…nqe4

2026-05-23 13:06:12 UTC

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In which year of their studies would you expect that university students of mathematics understand the above points?
I ask partly because my own first encounter with the axiom of choice was related to the proof that every vector space has a basis.
Courtesy of our teaching assistant early during the first-year linear-algebra course.
@npub1nf4…nqe4

2026-05-20 04:12:06 UTC

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It's been said many decades ago that economists successfully predict eleven out of three recessions...
@npub1z3l…txvc @npub1wkr…yvj6

2026-05-17 13:55:39 UTC

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Thank you very much.
I ought to educate myself some day about the way Newton's law of gravitation can be derived from relativity theory as an approximation.

2026-05-17 11:53:05 UTC

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A serious question, though the answer is likely above my head:
How can we understand the similarity between these two formulas in the light of non-classical physics?
*
A bit of humor from about a century ago:
Two physics professors talking during examination time:
"How can your exam questions be the same as last year's?!"
"The questions remain the same, the answers are different!"
@npub1nf4…nqe4

2026-05-15 02:57:07 UTC

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wrote:
«in a hundred years the only languages people will still care about are lisp and ada, right.»
Yes...
It must be redundant to recall another old quote, whose author I have also forgotten, alas, that whatever those languages are, they will be called Fortran.
Perhaps the choice of name ought to be modernized, but only the name.
Ha ha only serious...
@npub1s35…meq8 @npub1ums…7ra6 @npub1vlc…mzqq

2026-05-14 13:07:02 UTC

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Hyperlinked to the adage about Algol being an improvement to its successors.
I forget the attribution, alas.
Perhaps someone of the caliber of Dijkstra or Kay.
@npub1fp0…54p5 @npub1vlc…mzqq

2026-01-18 11:44:55 UTC

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Right.
Was this an article saying that the domestication of cats started in northern Africa (perhaps Egypt) about four thousand years ago and it took about a couple of thousand years for domestic cats to spread throughout Europe?
If I recall correctly, I read something about that several months ago.
@npub1wd3…fe2c @npub1nf4…nqe4

2025-09-26 18:44:22 UTC

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Wasn't Petrov a Lieutenant Colonel?
@npub1aer…7756

2025-09-25 16:53:48 UTC

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wrote:
> [Hinton] coined the word "tesseract" for a 4-dimensional cube - a word mainly used by SF writers, not mathematicians.
I'm embarrassed I can't recall the author of
And He Built a Crooked House
—a short story about a house that folds into a tesseract.

2025-09-22 08:33:43 UTC

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wrote:
> it will always be the case that there *might* be particles at energies far too high for us to reach with whatever technology we develop
Yes.
By the way, isn't the goal of _observing_ such phenomena
one of the driving forces of today's astronomy?
@npub1nf4…nqe4 @npub1a97…mqm8

2025-09-21 05:40:34 UTC

If our Universe is being simulated on a computer,
some questions arise, ordered from least to most uncomfortable:
How often does the maintainer release a new version of the simulation software?
Does the administrator ever tweak operational parameters?
Does it run on high-availability infrastructure?
Do we exist in the production environment?
Is the purpose of this simulation the writing of a PhD thesis?
(Ha ha only serious.)
#Metaphysics
#Physics
https://ftp.ieji.de/media_attachments/files/115/240/677/514/755/175/original/3216b81753e8afbf.jpg

2025-09-16 19:28:28 UTC

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I should have made a deep study of Conway and Smith's book,
and of your paper on octonions, too.
These are beautiful things.
@npub1nf4…nqe4

2025-09-16 18:42:39 UTC

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wrote:
> I might almost be okay for something like this, maybe, squinting at it, if we had giant state-owned farms run directly by the Ministry of Agriculture or something.
That is exactly how it was under socialism.
Most people were _not_ OK with it at all,
but almost everybody was afraid to object.
@npub16gr…ua4j

2025-09-12 04:43:17 UTC

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Indeed, and worse than a quagmire.
Again, how many people think about the fate of science in Germany after 1933?
Some do, but are they enough?
This matter is bigger than physics,
but regarding the latter in particular,
was Smolin's _The Trouble with Physics_ about 15 years ago
a reasonable take?
@npub1p7u…kglz @npub1nf4…nqe4

2025-09-11 18:14:42 UTC

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One of the co-authors, Ivan Todorov (1933–2025), was a prominent Bulgarian mathematical physicist with contributions to quantum field theory.
I have it directly from some of his colleagues that he was highly respected.
No biographical page in the English Wikipedia.
In case someone would go to the trouble of seeking a translation, this is from the Bulgarian Wikipedia:
<https://bg.wikipedia.org/wiki/%D0%98%D0%B2%D0%B0%D0%BD_%D0%A2%D0%BE%D0%B4%D0%BE%D1%80%D0%BE%D0%B2_%28%D1%84%D0%B8%D0%B7%D0%B8%D0%BA%29>
@npub1nf4…nqe4

2025-09-10 17:09:47 UTC

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CT = Category Theory?
Asking for both is quite, quite ambitious.
But maybe I have the wrong mindset.
@npub1ylz…m76c @npub1nf4…nqe4

2025-09-08 20:33:07 UTC

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Is this about
"argue something"
or
"argue that something"
or
"argue about something"?
@npub1nf4…nqe4 @npub1lez…3yeq

2025-09-08 19:29:02 UTC

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By the way, would you say that functional programming
has already become practical in this sense?
*
@npub1nf4…nqe4

2025-09-08 17:16:58 UTC

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Would you clarify or qualify "co-opted", please?
@npub1nf4…nqe4

2025-09-07 19:08:46 UTC

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Would you say that this matches the protests five years ago,
in the summer of 2020?
(Does it match them in participation?)
@npub1xw7…r9m5

2025-09-05 15:59:01 UTC

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!
Again, thank you.
Great minds created CERN and great minds work there!
But is there another laboratory that can reproduce this result independently?
And a specific question, if I may.
In
"a value of (0.75 ± 0.13 (statistical + systematic) ± 0.16 (simulation)) g for the local acceleration of antimatter"
are 0.13 and 0.16 absolute errors or standard deviations?
@npub1nf4…nqe4

2025-09-04 21:13:49 UTC

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Thank you very much.
The significant part is just a single sentence at the end about an experiment just two years ago without details (I didn't follow reference 31), so I should "stay tuned".
@npub1nf4…nqe4

2025-09-04 17:12:54 UTC

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Does this imply something about gravitational properties of antimatter?
For example, whether it's possible or impossible that gravitational force between matter and antimatter makes them repel each other.
@npub1nf4…nqe4

2025-09-02 13:20:00 UTC

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Forgive me if it is obvious, just not to me, that the following is nonsense.
May I venture a non-educated guess that it can't be done in three dimensions, but maybe it can in four dimensions?
This doesn't match the problem,
just explains my thinking:
A can pass through B
and
B can pass through A,
if they are ellipsoids,
one "cigar"-shaped and one "disk"-shaped.
We can't make a triple with a third ellipsoid C in three dimensions,
but it ought to be possible in four.
@npub1nf4…nqe4 @npub12cu…d38p

2025-09-02 10:48:51 UTC

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I.e. find a counter-example showing that this particular asymmetrical relation is not transitive, or prove that it is transitive?
@npub1nf4…nqe4 @npub12cu…d38p

2025-09-01 14:10:03 UTC

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1. I'll skip expressiveness, at least for now.
2. Even today Unix is not _all_ that the users have.
Moreover, in the first two decades or so of its existence
there were quite a few operating systems _of significance_,
most of which are now abandoned.
At least some of the latter would have survived,
if there had been (greater) user demand for them.
3. Fifty years is the bar that the original design choice of representation (general text) has set.
@npub1326…gzqx @npub159a…j4zd @npub16hk…dqr9 @npub1unu…hpy6

2025-09-01 12:26:26 UTC

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Let's suppose arbitrary general text is replaced by a common structured data representation for passing data between unix processes.
What will that representation be?
Note at least three important requirements:
1. Must be expressive (this can be made more specific when time permits).
2. Must be acceptable to a good majority of the users.
3. Must last fifty years or more.
There are other requirements as well, but I think I can omit them here.
@npub1326…gzqx @npub159a…j4zd @npub16hk…dqr9 @npub1unu…hpy6

2025-09-01 06:43:38 UTC

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It's not a flaw, it's a tradeoff.
_Some_ tradeoff must be made here.
(Like in many other cases.)
@npub1326…gzqx @npub159a…j4zd @npub16hk…dqr9 @npub1unu…hpy6

2025-08-31 10:00:36 UTC

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Indeed.
Now, how to make Jeff Atwood and those who listen to him take heed?
Regrettably, I don't know...
🙁
@npub1p09…m5vl

2025-08-29 07:46:07 UTC

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Very much so indeed.
Take, say, BB (10¹⁰⁰) and raise it to the power of BB(10¹⁰⁰).
Still a small number...
I cannot imagine a glass that can contain math's beer 🙂.
NB: I am not saying such a glass doesn't exist;
I am saying I cannot imagine it,
like Hilbert's student who became a poet.
@npub1nf4…nqe4

2025-08-28 12:20:53 UTC

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I may want to find out if this is the same Prince Rupert as that after whom the tears of glass are named.
@npub1nf4…nqe4

2025-08-26 10:19:27 UTC

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Cold indeed, yes, millimeter wavelengths are _way_ below infrared light.
Whether it's only 1 or 10 or 1000 atoms per cubic centimeter, the force of gravity acts on them and it can take its time.
@npub1nf4…nqe4

2025-08-22 15:01:45 UTC

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Entropy in Shannon's sense, isn't it?
Wouldn't that mean that the quantity of information in it seems low?
@npub1nf4…nqe4 @npub1c3s…jdhn

2025-08-21 20:31:02 UTC

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From that Wikipedia article:
Applications
...
Laurance Doyle and others have suggested the application of Zipf's law for detection of alien language in the search for extraterrestrial intelligence.
...
The word-like sign groups of the 15th-century codex Voynich Manuscript have been found to satisfy Zipf's law, suggesting that text is most likely not a hoax but rather written in an obscure language or cipher.

2025-08-18 18:28:42 UTC

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There is an old joke about a Pole who was granted three wishes.
Each of his wishes was for China to invade Poland.
So the Chinese armies would pass through Russia six times.
@npub1xw7…r9m5 @npub1jvr…df0v

2025-08-17 11:00:07 UTC

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Yes and yes and yes.
Regarding the domestication of cats, I think that is definitely so.
(And Kipling told that story very nicely indeed.
Except that it may well not have happened in caves.)
I should refresh my memory about prehistorians' current take on the domestication of dogs (when and why).
@npub1nf4…nqe4

2025-08-17 10:01:13 UTC

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Neanderthals and Cro-Magnons interbred.
So it's the same with the birds, the bees—and the cats.
🙂
@npub1nf4…nqe4

2025-08-13 17:45:17 UTC

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Thank you.
I made a mistake, I should have asked about "self-adjoint operator".
@npub1nf4…nqe4 @npub14a5…9fse

2025-08-13 16:26:35 UTC

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wrote:
> In functional analysis and quantum physics, I'd say the definition of 'Hilbert space' is incredibly important!
Would you add "bounded operator" on par with it?
@npub14a5…9fse

2025-08-10 19:03:52 UTC

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"You see the world through your cynical eyes,
You're a troubled young man, I can tell."
(Styx, 1977 or 1978)
@npub1xw7…r9m5 @npub1dz5…l0nu @npub1wkr…yvj6

2025-08-07 13:37:35 UTC

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wrote:
> Actually, when you are a field scientist collecting data, it is very tempting to just collect away and leave the analysis and interpretation till later.
Regrettably, that is so.
There are archaeologists (some, not all!) who just excavate and collect finds (artifacts), the exciting part, but don't sit down to process them (analyze, publish, etc.), the "boring" part...
Nor do they let others do that...
@npub1nf4…nqe4 @npub12cu…d38p

2025-08-07 13:26:18 UTC

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wrote:
> Unless it is going to be completely obliterated anyhow, for example to make way for a motorway.
Yes, rescue excavations are very different from regular ones.
There is also the time pressure.
@npub12cu…d38p @npub1nf4…nqe4

2025-08-07 10:31:35 UTC

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Right.
Seriously, fired clay (with the right additives!) is the oldest artificial material (eight thousand years, if not more) and still going strong.
@npub1nf4…nqe4 @npub12cu…d38p

2025-08-07 09:59:15 UTC

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Er, that would be pyrogenics...
@npub1nf4…nqe4 @npub12cu…d38p

2025-07-26 07:44:22 UTC

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I am partial to Peter Sinfield's rhymes.
For example,
Confusion will be my epitaph
As I crawl a cracked and broken path...
(By the way, Greek theta used to turn into the F sound in Russian borrowings from Greek.)
[@Theorem_Poem](https://mstdn.social/@Theorem_Poem )

2025-07-21 06:22:29 UTC

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Right!
🙂
Now I can't resist telling this one (I heard it from an Australian, so you may well have heard it before).
A snake couple had no children.
Eventually they got advice to try on a wooden table and it helped, but they had to ask for an explanation, which was:
"You are adders, you need log tables to multiply."
@npub1wyj…sqyp @npub1nf4…nqe4

2025-07-21 05:52:05 UTC

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I am sorry, I thought it was just obvious...
I was thinking of eμ, though I cannot think of a case where one would actually want to multiply a mean by exp 1.
Maybe the birds can 🙂.
@npub1wyj…sqyp @npub1nf4…nqe4

2025-07-20 11:12:50 UTC

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> emus ... are very mathematical birds
With a mathematical name.
🙂
@npub1wyj…sqyp @npub1nf4…nqe4

2025-07-13 15:22:15 UTC

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> Literally this means "Comrade Building the Nation". It's a joke about "Make America Great Again".
Yes, but I see more here.
"Build" was a keyword in Soviet bloc propaganda and I strongly suspect it has been more or less the same in China.
As in:
"We build for the Motherland."
"Let's keep building tirelessly, comrades."
"Build a new society."
Etc.
@npub1nf4…nqe4

2025-07-11 17:17:48 UTC

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> unless you keep your mouth shut and don't do anything overtly stupid, which is its own kind of demonstration of intelligence
There is even an ancient proverb:
if you had remained silent, we would still think you were clever.
@npub1qnq…sy30 @npub1xw7…r9m5 @npub13f9…ech3

2025-07-06 11:49:24 UTC

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> save some of your neighbors for a while
The last three words are key.
That would help only during the initial, milder parts of the harm of climate change.
When hundreds of millions of people start migrating, those measures won't prevent the crumbling of all of civilization, not just the one "we're used to"...
🙁
@npub1nf4…nqe4

2025-07-01 15:09:57 UTC

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In that case I expect protracted arguments about what a proof is.
Possibly bitter arguments.
[@fractal_timescales](https://mathstodon.xyz/@fractal_timescales ) @npub1nf4…nqe4

2025-07-01 09:22:25 UTC

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P.S.
Serrano might be after a Fields Medal.
@npub1nf4…nqe4

2025-07-01 08:59:24 UTC

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> This is not what I'd call "complete discretion".
No, it isn't.
However, this is product placement.
By the way, if a solution is proposed (either way), it will take a while to check it, won't it?
That won't stop interested parties from advertising it immediately as The Solution, I shouldn't wonder...
@npub1nf4…nqe4

2025-06-19 09:04:50 UTC

I thought the Soviet record with N1 would be hard to beat:
four launch attempts, four dismal failures.
I was wrong.
#SpaceX
_________
N1 was a huge launch vehicle with 30 (thirty) engines in the first stage.
It should have been used to send people to the Moon; abandoned in 1974.

2025-06-17 10:57:26 UTC

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Aren't the greenhouse effects of carbon compounds nonlinear?
E.g. is the amount of energy reflected back to Earth by carbon compounds in the atmosphere a nonlinear function of the quantity of those compounds?
Yes, I realize that even asking a question like that may be an oversimplification, possibly a bad one.
@npub1nf4…nqe4

2025-06-15 04:15:38 UTC

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Thank you for the clarification.
Yes, the opposite side of the Earth, or laterally, so travelling through some part of the Earth's body: I don't know how well (with what precision) a direction can be determined.
@npub1nf4…nqe4

2025-06-14 19:44:50 UTC

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<">
a few pulses coming from below DON'T have their polarization flipped. And nobody knows what makes those! Enough explanations have been ruled out
</">
I suppose the latter includes ruling out that these pulses came from the opposite side?
@npub1nf4…nqe4

2025-06-12 09:02:34 UTC

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In Europe, too.
#NoKings
#Solidarity
#Solidarnosć, who won in Poland in 1989

2025-06-09 23:31:10 UTC

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It did strike me that much of this, if not almost all of it, is not _specific_ to Applied Category Theory at all.
Probably that should have made me realize it was composed by artificial intelligence (if I was reading it in the light of day, maybe 🙂).

2025-06-06 17:02:19 UTC

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You are very kind, thank you very much, but that would be too much trouble; I was surprised that the article didn't mention any.

2025-06-06 16:32:32 UTC

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No estimate of the mass of the Oort cloud?
Not even a lower bound?
By the way, a spiral is a very old symbol of the Sun.

2025-06-05 09:28:14 UTC

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> a collection of individuals each rationally maximizing their own utility
But what EXACTLY is _rational_ in this context?
An adequate, precise, explicit definition seems like it would require quite a bit of effort.
(I am even tempted to imagine it might require something on the order of an axiomatization of economics, though that is a grand but fairly useless image...)

2025-05-31 17:53:54 UTC

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How many Americans know the consequences of what happened to German universities in the 1930s?
Different mechanisms, but the _consequences_?
(In one sentence, German universities ceased to be the best in the world, at least in sciences.)