Nostr notes by Markus Redeker 🐘

I want to be in this cave! 🙂

2026-10-25T10:55:20Z

In reply to nevent1q…4yty
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I want to be in this cave! 🙂

There must be an enormous number of one-person servers, so the ...

2026-10-01T21:58:25Z

In reply to nevent1q…4gzj
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There must be an enormous number of one-person servers, so the number of surviving servers need not tell much about the Fediverse as a whole.

Do you too see rotating acorns? 🙂

2026-09-13T21:14:49Z

In reply to nevent1q…mdqd
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Do you too see rotating acorns? 🙂

“But maybe it's renewable if one is willing to solve an ...

2026-09-07T19:39:36Z

In reply to nevent1q…ksd6
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“But maybe it's renewable if one is willing to solve an already solved problem without looking at the existing solution.” — Or just change our standards what counts as a solution, requiring more than just the existence of a proof.
We are already a bit in this world. Everyone still waits for a human-readable proof of the four-colour-problem. Or for a really short classification of the finite groups. Whoever found it would be as famous as the first discoverer of a proof. We will need to strengthen this viewpoint.

Do you want to continue drawing your comics in this style? It ...

2026-08-19T17:55:04Z

In reply to nevent1q…jhmy
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Do you want to continue drawing your comics in this style? It won't be bad. 🙂

Gandalf creating smoke rings... 🙂

2026-06-30T17:04:50Z

In reply to nevent1q…jzk8
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Gandalf creating smoke rings... 🙂

The subtitle of the Science article has, “A bot may be to ...

2026-06-28T11:08:04Z

In reply to nevent1q…fm0u
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The subtitle of the Science article has, “A bot may be to blame“. No, not the bot: There was a person, probably somewhat higher up in the Springer hierarchy, who set the bot loose, and this person is to blame.

(There is now also an article in arXiv by the science historians who researched the whole thing: https://arxiv.org/abs/2605.17534)

OK, that makes sense: Starbucks US owned stock of Starbucks ...

2026-06-27T08:03:50Z

In reply to nevent1q…a8jt
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OK, that makes sense: Starbucks US owned stock of Starbucks Korea, which it sold to EMart so that it could control Starbucks Korea. And in that purchase contract was a clause that allows it for Starbucks US to forcibly buy the stock back.

Without knowing about Starbucks Korea, the whole original paragraph could not be understood.

Many thanks for finding out!

I now consider this paragraph a possible AI hallucination, until ...

2026-06-27T07:24:19Z

In reply to nevent1q…uhpf
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I now consider this paragraph a possible AI hallucination, until someone finds a source that supports it.

Thanks. My problem was especially the phrase, “the Korean ...

2026-06-26T19:02:10Z

In reply to nevent1q…e0cj
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Thanks. My problem was especially the phrase, “the Korean shares”. So E-Mart is a separate company from Starbucks (since E-Mart is Korean), but it is possible for them to have an agreement that allows Starbucks to forcibly buy the E-Mart stock from whoever owns it at a later time? I did not think this was possible.

Why do you think so?

2026-06-26T14:28:36Z

In reply to nevent1q…0fr3
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Why do you think so?

Fascinating. And what an illustration for Hanlon's Razor, by ...

2026-06-26T14:28:12Z

In reply to nevent1q…epwx
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Fascinating. And what an illustration for Hanlon's Razor, by the way.

I have however a question to the Fediverse, especially to the finance experts: In the text, there is a paragraph,
“Buried in the franchise agreement between E-Mart and Starbucks US is a punitive ‘Call Option’ clause: if the local partner causes damage to the global brand's equity, Starbucks US headquarters reserves the right to forcibly buy back all Korean shares — at a 35% discount from fair market value.”
What exactly does this mean?

#AskFedi #Finance #Starbucks #Korea

Also very important: “Both Scarlata and Gingras are concerned ...

2026-06-26T10:48:39Z

In reply to nevent1q…pgpy
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Also very important: “Both Scarlata and Gingras are concerned that papers by less prominent scientists have disappeared as well without anyone realizing.”

Don't forget this.

What I would like to see is a variant of this animation in which ...

2026-06-05T17:11:54Z

In reply to nevent1q…5q83
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What I would like to see is a variant of this animation in which the sphere slowly rotates — it seems appropriate. Could you create one?

An asteroid with trading, sea-anemone-like extraterrestrials. ...

2026-06-04T19:08:34Z

In reply to nevent1q…wymm
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An asteroid with trading, sea-anemone-like extraterrestrials. (The local stock exchange of its planetary system, maybe?)

And could you please create a version in which the sphere slowly rotates?

Ah, you are right, 1 is a proper divisor of every non-zero ...

2026-02-06T08:29:34Z

In reply to nevent1q…anxn
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Ah, you are right, 1 is a proper divisor of every non-zero integer. I must have confused it with the eternal question whether 1 is a prime number. 🙂

(But that also means that proofwiki text is wrong at two places.)

No, one does not consider 1 as a proper divisor of 21. And one ...

2026-02-04T17:21:08Z

In reply to nevent1q…m0cl
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No, one does not consider 1 as a proper divisor of 21. And one does not write 21 as “12” either. 🙂
Do not trust this text.

Interestingly, the → symbol is on my (German) keyboard, as ...

2025-12-15T12:50:27Z

In reply to nevent1q…8nwc
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Interestingly, the → symbol is on my (German) keyboard, as AltGr+i.

“Phobos is slowly drifting toward Mars. Tens of millions of ...

2025-11-12T17:51:52Z

In reply to nevent1q…jecw
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“Phobos is slowly drifting toward Mars. Tens of millions of years from now, it will crash land.” — and in the meantime, it works as a perfect potato impersonator. 🙂

Sometimes there are binary operations, but in special cases, they ...

2025-10-31T11:25:10Z

In reply to nevent1q…r7l0
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Sometimes there are binary operations, but in special cases, they interact and cannot be separated anymore. This seems to be the case with ternary rings (https://en.wikipedia.org/wiki/Planar_ternary_ring), which are a generalisation of ordinary rings.

A ternary ring is an algebraic system with a single operation 𝑇(𝑎, 𝑏, 𝑐) that satisfies certain conditions. An ordinary ring is a ternary ring with 𝑇(𝑎, 𝑏, 𝑐) = 𝑎𝑏 + 𝑐.

Ternary rings are used in connection with affine planes, which are generalisations of the Euclidean plane. In them, one can define a coordinate system by introducing crossing bundles of parallel lines, as in the Euclidean case. For the coordinates themselves, one can define a multiplication and an addition by geometrical means. In the Euclidean plane and in all affine geometries in which Desargues' theorem (https://en.wikipedia.org/wiki/Desargues%27s_theorem), the resulting algebraic structure is a division ring. But there are other affine planes in which the theorem is not true: There, the coordinates form at least a ternary ring.

“‘When I consume AI art, it also evokes a feeling, good, bad, ...

2025-10-12T13:59:35Z

In reply to nevent1q…fpl9
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“‘When I consume AI art, it also evokes a feeling, good, bad, neutral, whatever. Until I find out that it's AI art. Then I feel deflated, grossed out, and maybe little bit bored. ...’” [...] Previously, similar attitudes existed towards recorded music. Today, we allow ourselves to enjoy recorded music, though we still value live performances more.” — With music, we have learned to understand a recording as an expression of the thoughts and feelings of a real person. It is this real person that makes music or works of art interesting. (Why, I cannot say, but at the same time it is completely obvious to me.) If we had an AI with a personality, we would find its works interesting.

There is a promise in the art of a real person (or even in any of their utterances). When they say something interesting, you can be relatively sure that the next thing they say is also interesting. When you see a painting by a real person and its general structure looks good, then you can be relatively sure that all the details are also right, and you can lose yourself in the image. This is not true with current AI. You must be always on guard.

Question: How big is the number of persons in your country would ...

2025-05-03T17:02:15Z

Question: How big is the number of persons in your country would donate 1% of their income to fight global warming?
Answer: Much bigger than you think.

A recent global survey (https://www.nature.com/articles/s41558-024-01925-3.pdf) found that in all surveyed countries, people estimate the number of people who support climate action too low, usually about 2/3 of the real number. And 89% of the population worldwide want stronger action to fight the climate crisis (https://www.theguardian.com/environment/2025/apr/22/activate-climate-silent-majority-support-supercharge-action).

You can check at https://gccs.iza.org/rankings the values for your country.

#Climate #ClimateCrisis

„Ich denke er hat's verdient.” — Bitte sag das nicht. ...

2025-03-01T11:50:24Z

In reply to nevent1q…vv2q
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„Ich denke er hat's verdient.” — Bitte sag das nicht. Du entmenschlichst dich damit selber ein Stück.

Möge Lindners Politik erfolglos sein. (Das ist mit der letzten Wahl ein wenig eingetreten.) Aber sein Privatleben sei glücklich wie das von jedem von uns.

@npub1hq7…nytw Bei so viel schlechten Nachrichten verbreite ich ...

2025-02-07T09:44:52Z

Perspective Daily (npub1hq7…nytw) Bei so viel schlechten Nachrichten verbreite ich mal eine gute (https://perspective-daily.de/article/3555-erstes-jahr-ohne-tote-fussgaenger-diese-stadt-zeigt-was-tempo-30-kann/GGVlsnEa?pk_campaign=mstdn-user):

Die Stadt #Bologna hat vor einem Jahr auf fast allen Straßen Tempo 30 eingeführt (und dazu auch Radwege und Fußgängerzonen gebaut).

- Das Resultat ist, dass es im letzten Jahr zum ersten Mal seit 1991 keinen einzigen für Fußgänger tödlichen Unfall gab.
- Die Zahl der Verkehrstoten insgesamt hat sich letztes Jahr halbiert.
- In Bologna gibt es jetzt 11.000 Autos weniger und 10% Fahrräder mehr.

Ich hatte nicht gedacht, dass Fahren über 30 km/h so gefährlich ist.

#Fahrrad #Radfahren #Verkehrswende #Natenom #Solarpunk

Text des Bildes: „Wir dürfen nicht schweigen! Rechte Parteien ...

2025-01-25T13:55:16Z

In reply to nevent1q…5mlf
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Text des Bildes:
„Wir dürfen nicht schweigen!
Rechte Parteien und die, die sich ihnen anbiedern, führen uns nicht in ein besseres Leben, sondern in eines, in dem sich soziale Ungerechtigkeiten verstärken, Hass und Gewalt normal werden und Faschismus regiert.
Wir stehen ein für Demokratie, Vielfalt, Menschenrechte und Toleranz.
Eine Menschenkette entlang der Bannmeile um unser Rathaus soll das Zeichen dafür sein.

Macht mit! Wir sind viele!

Hamburg wehrt sich
Keine Nazis in unser Rathaus!

31.01.25, 14 Uhr
Reesendamm Ecke Jungfernstieg
https://menschenkette-hamburg.de“

There is an ongoing petition / open letter (https://leavex.eu) ...

2025-01-17T19:57:16Z

There is an ongoing petition / open letter (https://leavex.eu) that asks all European politicians and leaders to leave #X / #Twitter. It still needs a lot of signatures!

#eXit #eXodus #SocialMedia

“I'm curious, is it because of this?” — Yes, that's ...

2025-01-11T11:28:50Z

In reply to nevent1q…hulz
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“I'm curious, is it because of this?” — Yes, that's why. The number itself is not really important, but it is a well-known part of mathematical folklore.

1729. If you know why it is this number, you belong to the ...

2025-01-11T11:17:04Z

In reply to nevent1q…m5gk
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1729. If you know why it is this number, you belong to the intended audience. 🙂 (But even if not, you still can get an account.)

Thanks. The perihelion was at 1:22:32 p.m. UTC ...

2025-01-04T19:22:32Z

In reply to nevent1q…ckdu
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Thanks.

The perihelion was at 1:22:32 p.m. UTC (https://www.theweather.net/news/science/when-is-perihelion-in-2025-the-day-when-earth-is-closest-to-the-sun.html).

Today is the second John Mastodon Day: On this day two years ago ...

2024-12-16T14:37:21Z

Today is the second John Mastodon Day: On this day two years ago a misinformed journalist created the personality of “John Mastodon, the founder of a competing social media company named after himself“ (https://web.archive.org/web/20221216232836/https://www.mediaite.com/opinion/hypocrisy-and-fear-all-the-way-down-at-twitter). Users happily accepted the newcomer, turned him into a running gag (https://boingboing.net/2022/12/18/mastodon-users-embrace-columnists-funny-error-about-a-fictitious-john-mastodon.html) and made him patron saint of Mastodon.

We celebrate John Mastodon Day because on this day, John Mastodon made Mastodon visible to the mainstream media. He will protect us as long as he exists.

#JohnMastodon #JohnMastodonDay #Mastodon #OnThisDay

“It would be wonderful if we could visualise every mathematical ...

2024-12-08T12:34:45Z

In reply to nevent1q…ehmc
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“It would be wonderful if we could visualise every mathematical problem with a glorious bird’s-eye view that showed the whole structure of the solution space at a glance.” — But is finding a good bird's-eye view not really the whole purpose of mathematical research? 🙂

Yes, #Oresme was quite interesting. I know him for two other ...

2024-12-01T19:57:49Z

In reply to nevent1q…28vf
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Yes, #Oresme was quite interesting. I know him for two other achievements:

1. Relativity of motion: He had already the famous “ship argument” that #Galileo used to show that physics in a moving object must be the same as in a standing one — the only difference is that Oresme, living in Paris, used a ship on a river and not on the sea. (https://todayinsci.com/O/Oresme_Nicole/OresmeNicole-Forerunner.htm)

2. He proved the divergence of the harmonic series. (https://en.wikipedia.org/wiki/Nicole_Oresme#Mathematics)

There is a small rant about boring definitions in Klaus ...

2024-11-15T16:35:05Z

In reply to nevent1q…hgxv
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There is a small rant about boring definitions in Klaus Jänich's “Topology” (in Section 8.5 about paracompactness) where he makes exactly the same point. It also inspired my own posting.

Think of a mathematical definition as having two sides: a user ...

2024-11-15T14:34:33Z

Think of a mathematical definition as having two sides: a user side and a verification side.

The verification side is what you usually see in a book or paper: a minimalistic description that makes it as easy as possible to verify that a certain mathematical object has property X.

The user side is usually presented in form of one or more theorems that follow the verification side. They provide the rich mental image you need to have in mind to think of property X or use it in a mathematical argument — its real nature, so to speak.

For, example a dense subset \( D \subseteq \mathbb R \) is defined by the property that if there are two different elements \( x \) and \( y \) in \( D \), then there is a third one between them. This is the verification side. The user side is: If there are two different elements \( x \) and \( y \) in \( D \), then there are infinitely many others between them!

#Mathematics #MathEducation #Definitions

“My Viking history is weak.” – Read “Children of Ash and ...

2024-10-19T19:41:01Z

In reply to nevent1q…wpvg
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“My Viking history is weak.” – Read “Children of Ash and Elm” by Neil Price. It must be the best book on Vikings that is currently available. I thought I knew a bit about history, but the book brought more or less on every page something that was new to me. And the Vikings were a really strange people!

Kafka? Der war die meiste Zeit Versicherungsangestellter und ...

2024-08-27T17:43:16Z

In reply to nevent1q…qzn9
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Kafka? Der war die meiste Zeit Versicherungsangestellter und (tatsächlich!) stiller Teilhaber einer Asbestfabrik (https://de.wikipedia.org/wiki/Franz_Kafka#Berufsleben). „Kafkas ruhiger und persönlicher Umgang mit den Arbeitern hob sich vom herablassenden Chefgebaren seines Vaters ab.”

Franz Kafka als Teilhaber einer Asbestfabrik ist dann allerdings mein unnützes Wissen des Tages. 🙂