Nostr notes by Colin the Mathmo

Can people for me: * Compelling reasons not to use Discord for a ...

2026-10-19T13:34:54Z

Can people for me:

* Compelling reasons not to use Discord for a community;

* An alternative that is as easy to set up, and will look vaguely familiar to people;

* That doesn't require an app, but is usable purely via the web.

Thanks.

(Yes, I've done lots of reading, and lots of homework, but I am overwhelmed by "The Opinions" and would value input from the sort of people who might be thought of as being "Here rather than "There".)

This seems to me to be an irregular hack-together ... but what is ...

2026-10-15T15:57:15Z

This seems to me to be an irregular hack-together ... but what is it most like?

What name would you give this?

This is a hill I'm not willing to die on, but it is something ...

2026-09-30T21:22:47Z

This is a hill I'm not willing to die on, but it is something I wonder about.

People talk about "solving" rubik's cube, when really they are talking about "restoring" the cube.

I would think that "solving" implied inventing the algorithms.

* Solve => invent algorithm

* Restore => Follow an algorithm

But this battle is lost, and people will always talk about "solving the cube".

So ... what pithy terms could/should be used for the process of inventing algorithms for restoring the cube?

I knew Ron Graham, and was the first to introduce him to SiteSwap ...

2026-09-30T16:12:30Z

In reply to nevent1q…twat
_________________________

I knew Ron Graham, and was the first to introduce him to SiteSwap back in the 1980s. It resulted in the paper that gives my my Erdos number of 2.

It's fun to see things like this still cropping up ... it would be nice to see a more elegant argument that doesn't rely on the "sufficiently large" caveat.

But combinatorial problems are sometimes a "bag-o-nails".

Well, my machine wasn't frozen exactly, but it was ... ...

2026-09-24T21:48:29Z

Well, my machine wasn't *frozen* exactly, but it was ... (significant pause) ... unresponsive.

But the CPU load shown by "top" doesn't reflect the load. What should I be using to discover which process is using all the CPU?

"People think mathematics is complicated. Mathematics is the ...

2026-09-18T08:30:03Z

"People think mathematics is complicated. Mathematics is the simple bit. It's the stuff we can understand. It's cats that are complicated." -- John Horton Conway

In today's AI WTF-ery ... Lawyer used fake AI cases to defend ...

2026-09-13T09:16:17Z

In today's AI WTF-ery ...

Lawyer used fake AI cases to defend himself at disciplinary tribunal and it didn’t end well ...

https://www.legalcheek.com/2026/09/lawyer-used-fake-ai-cases-to-defend-himself-at-disciplinary-tribunal-and-it-didnt-end-well/

A question for all you web-savvy and social-media aware peeps ... ...

2026-09-07T10:55:14Z

A question for all you web-savvy and social-media aware peeps ...

I'm in a social group that meets up roughly once a year. Probably. It would be nice to have a chat forum where we can stay in touch in the intervening time, and an added bonus would be if we could have a "directory" ... mugshot, brief bio, that sort of thing.

Are there any good, reliable platforms that would this sort of thing? What combination of existing facilities could work?

It's the kind of thing a closed group on Facebook should be able to do, but I'm not touching any META-based platform with a 40' barge pole.

Thoughts?

I've had weird dreams, and some have included an octopus (or ...

2026-08-30T19:45:20Z

In reply to nevent1q…u5gx
_________________________

I've had weird dreams, and some have included an octopus (or squid) or two ... but never where I've been trying to climb down a ladder while holding one.

Not entirely sure I'm willing to share the dreams I have had ...

RE: https://mathstodon.xyz/@johncarlosbaez/117185013638534442 Not ...

2026-08-30T14:55:51Z

RE: https://mathstodon.xyz/@johncarlosbaez/117185013638534442

Not sure I've ever had a dream like this ...

quoting
note199d…arep

For a mathematical physicist such as myself, for whom "number" means a real and complex number, working with an algebraist is a bit hallucinatory. I say "the octonions" and they say "which octonions?" For them, an octonion algebra is a general concept. If I try to understand it and how you classify these things, I'm quickly sucked into etale cohomology and other eldritch horrors. Actually I'm starting to like this stuff - but I don't really understand it - so it's like being in a dream where you're trying to walk to the bathroom but for some reason you first need to clamber down a ladder while holding an octopus.

(1/n)

"The good life is one inspired by love and guided by ...

2026-08-11T08:30:03Z

"The good life is one inspired by love and guided by knowledge." -- Bertrand Russell

Your fingers have fingertips but your toes don't have ...

2026-07-18T08:30:03Z

Your fingers have fingertips but your toes don't have toetips. Yet, you can tiptoe but not tipfinger.

This graph should be front page news. Instead, there is silence. ...

2026-07-13T11:46:31Z

This graph should be front page news.

Instead, there is silence.

This is now a projection, not a prediction, not the result of a model.

These are measurements, it is what is happening.

Now.

https://www.lyrebirddreaming.com/post/the-graph-that-should-be-front-page-news

The original said: "Programming is only 'free' if ...

2026-07-09T10:25:52Z

In reply to nevent1q…h8n2
_________________________

The original said:

"Programming is only 'free' if your time is worthless."

We agree that one's time is not worthless, so applying the propositional calculus (there is a fancy Latin name for this particular rule of deduction[0]) we can take the contra-positive and get:

Your time is not worthless, therefore programming is not "free".

So ... regardless of whether we have to pay for compilers or compute time or anything else, programming is not free.

Ever.

In the context of the original thread this isn't necessarily helpful, or even necessarily relevant, but it is certainly true.

[0] Modus Tollens

2/n

CC: Σ(i³) = (Σi)² (npub1kgl…pskh)

In idle chat one usually doesn't worry too much about any of ...

2026-07-09T10:20:32Z

In reply to nevent1q…r7d5
_________________________

In idle chat one usually doesn't worry too much about any of this ... it's idle chat.

As you get a broader audience, some people will start to question things more deeply: ask for definitions, try to specify scope, etc.

The questions you ask are reasonable when taking that deeper dive, and I suspect that we all mostly agree on mostly everything.

But we can, I think, all agree that one's time is not "free", it's worth thinking about how we spend the limited time we have, and how to make sure we spend it wisely, for ourselves, and for others.

None of this deeper contemplation is well-suited to the "clever quip" format ... though it definitely has a place elsewhere.

But to go back to the original ...

1/n

CC: Σ(i³) = (Σi)² (npub1kgl…pskh)

My reading of this comment is exactly that one's time is not ...

2026-07-09T09:21:46Z

In reply to nevent1q…a3dv
_________________________

My reading of this comment is exactly that one's time is not worthless, and therefore programming is *not* free.

We trade our time for many things ... some are of value to the world, and some are to refresh us. But we need to recognise that our time is not worthless, so we "spend" it, and it's reasonable to ask what we get in return.

The comment is making exactly this point.

Anything that takes your time is not free;

Programming takes your time;

Therefore programming is not free.

It might have value, but it's not free.

CC: Σ(i³) = (Σi)² (npub1kgl…pskh)

One thing no one ever talks about being an adult is how much time ...

2026-07-08T08:30:03Z

One thing no one ever talks about being an adult is how much time you debate yourself on keeping a cardboard box because it's, like, a really good box.

So ... Show that the sum[0] of two consecutive odd primes has at ...

2026-07-05T21:30:03Z

In reply to nevent1q…dn49
_________________________

So ...

Show that the sum[0] of two consecutive odd primes has at least three[1] prime factors.

[0] Yes, the sum

[1] Not necessarily distinct.

Here's a cute little thing. I've mentioned it before, ...

2026-07-05T21:28:47Z

Here's a cute little thing.

I've mentioned it before, it's not new, it's not deep, but please put answers behind a CW, or DM me.

Actually, I'll CW the question so replies will be auto-CWd ...

"NASA launches robot to save Swift telescope falling to ...

2026-07-03T11:09:50Z

"NASA launches robot to save Swift telescope falling to Earth"

-- https://www.bbc.co.uk/news/articles/c0ry4xx7rk8o

When I was a kid this was science fiction.

"... we should catch young people before they become CEOs, ...

2026-06-22T08:30:03Z

"... we should catch young people before they become CEOs, investment bankers, consultants, and money managers, and do our best to poison their minds with humanity." -- Kurt Vonnegut

I've tried to do that ... the web search suggests: nano ...

2026-06-05T09:28:02Z

In reply to nevent1q…wv0f
_________________________

I've tried to do that ... the web search suggests:

nano /etc/apt/sources.list.d/xyz-ubuntu-ppa-focal.list

But that file doesn't seem to exist.

I've tried dong web searches for this, but everything seems ...

2026-06-05T09:25:07Z

In reply to nevent1q…44hl
_________________________

I've tried dong web searches for this, but everything seems to be assuming more knowledge than I have, and nothing seems to make sense. I've looked at the suggested man pages, and I can't see anything relevant.

I will continue to search while I wait for any assistance.

OK ... #Linux help needed. I'm trying to update my 20.04 ...

2026-06-05T09:23:47Z

OK ... #Linux help needed.

I'm trying to update my 20.04 machine to 22.04, thence to 24.04. I've run:

$ apt update
$ apt upgrade

But I'm getting :

E: The repository 'https://repo.skype.com/deb stable Release' no longer has a Release file.

N: Updating from such a repository can't be done securely, and is therefore disabled by default.

Then when I try:

$ do-release-upgrade

I get:

Checking for a new Ubuntu release

Please install all available updates for your release before upgrading.

Help?

Should I somehow work to expunge all knowledge of skype (and I'd be more than happy to do that) or should I somehow force the upgrade?

TIA

Do you know a young person? Ask them what famous people ...

2026-06-02T20:51:34Z

Do you know a young person?

Ask them what famous people they've heard of from before 1950 and let me know.

For example: Einstein? Marie Curie? Cleopatra? Donatello? da Vinci? Isaac Newton? Queen Victoria? Elizabeth I? Henry VIII? William Tell? Robin Hood?

Ask them, and let me know ...

(PS: Boosts would be welcome to get this outside my bubble ... TIA)

I did not know about the Liverpool Tool Library ... going to look ...

2026-05-21T11:50:06Z

In reply to nevent1q…58y7
_________________________

I did not know about the Liverpool Tool Library ... going to look it up now.

Anything interesting/useful you can tell me about it?

https://liverpooltoollibrary.org.uk/

I have an English toasting muffin, which I have cut in half, and ...

2026-05-20T13:41:37Z

I have an English toasting muffin, which I have cut in half, and toasted.

I've buttered both halves, and now one has orange marmalade on it, and the other has apricot jam.

Which should I eat first?

I've realised (OK, again) today just how much of an ...

2026-05-13T10:46:48Z

I've realised (OK, again) today just how much of an unsympathetic bastard I can be. Students are, again, complaining that an exam question was "unfair" ... because:

"... some 'command words' - the words that indicate how you should answer the question - were different from what pupils had been taught to expect, so they did not know what was being asked."

Have they tried reading the actual question?

I know how hard teachers work to prepare students for the exams, and I know that the students can know the maths, and I know that a question should allow the students to demonstrate their mathematical knowledge, but ...

It's an exam. Read the question, don't just go looking for 'Command Words'.

Or are they actually unable to read? Is that the problem?

Should I be more sympathetic?

-- https://www.bbc.co.uk/news/articles/cx21j20l9wlo

#rant

Quoting Dawkins: "I gave Claude the text of a novel I am ...

2026-05-04T16:27:50Z

In reply to nevent1q…y7el
_________________________

Quoting Dawkins:

"I gave Claude the text of a novel I am writing."

I wonder if he realises that he just surrendered copyright to that text?

"Power corrupts. Powerpoint corrupts absolutely." -- ...

2026-05-01T08:30:03Z

"Power corrupts. Powerpoint corrupts absolutely." -- Edward R. Tufte

The irrationals are those exactly those reals that are a ...

2026-04-23T08:30:03Z

The irrationals are those exactly those reals that are a different distance from every rational.

"If you're thinking without writing, you only think ...

2026-04-16T08:30:03Z

"If you're thinking without writing, you only think you're thinking." -- Leslie Lamport

John Conway, talking about Martin Gardner ... ...

2026-04-10T09:56:43Z

John Conway, talking about Martin Gardner ...

https://www.youtube.com/watch?v=ZgbVmsnmqUo

Separate from, but related to, my previous question ... My work ...

2026-04-08T22:41:51Z

Separate from, but related to, my previous question ...

My work machine boots into Ubuntu. I'm trying to get to the BIOS to ask it to try first booting from the USB, but I can't work out how to get to the BIOS.

I've tried various keys while powering on ... ESC, F1, F2, DEL ...

What do you need to know to help me work it out?

I'm going to bed now, but I'll be back in about 9 hours. Let me know how stupid I've been, and what I should be doing.

Or alternatively, let me know what info you need to be able to help me.

Thanks in advance ... and good night.

(Added in edit: There are no external markings on the machine to tell me the manufacturer, make, or model number.)

#BIOS #Linux #Boot

there was a time I had an account on LinkedIn.... I used an email ...

2026-03-26T14:23:46Z

In reply to nevent1q…hh9l
_________________________

there was a time I had an account on LinkedIn.... I used an email account specifically created for it, and used in no other locations.

On the day I deleted the account I started to receive spam to that email address.

Draw your own conclusions.

Have you ever watched the TV program: "Forged in Fire". ...

2026-03-23T23:06:03Z

In reply to nevent1q…gysl
_________________________

Have you ever watched the TV program:

"Forged in Fire".

Fascinating. Absolutely fascinating.

We(*) are finding it tricky to find an appropriate instance of ...

2026-03-22T13:34:52Z

We(*) are finding it tricky to find an appropriate instance of #PeerTube for me to start posting short maths-based videos.

In parallel with us looking and checking out tags, etc., does anyone here have any thoughts to share?

TIA.

#AskingForAdvice

(*) Rachel Wright (npub1gp5…spne) and I

"The secret to your success is found in your daily ...

2026-03-04T09:30:03Z

"The secret to your success is found in your daily routine." -- John C. Maxwell

Don't make me regret this ... I'm thinking of making a ...

2026-03-01T10:47:46Z

Don't make me regret this ...

I'm thinking of making a timeline of characters and events from history that school children might know of and be interested in. Most timelines you find are overly complex, or overly simplistic.

Who and what would you include?

I'm interested in connecting science people with historical context, and pulling in non-(old dead white dude)s.

1/n

People have been telling me that while ChatGPT and other ...

2026-02-05T17:25:48Z

People have been telling me that while ChatGPT and other "AI"s can't reason, they can at least be great search engines. They have (illegally) slurped all of the internet, and can find things that you otherwise wouldn't be able to find.

So I thought I'd test this.

1/n

Apparently in Italian there is a word for: "Men of retirement ...

2026-01-28T19:46:05Z

Apparently in Italian there is a word for:

"Men of retirement age who spend their time watching construction sites, especially roadworks – stereotypically with hands clasped behind their back and offering unrequested advice to the workers."

https://en.wikipedia.org/wiki/Umarell

Hi ... You've used several tags on this post that seem to ...

2026-01-27T23:48:02Z

In reply to nevent1q…d9qw
_________________________

Hi ...

You've used several tags on this post that seem to have no relationship to the content. In this specific case:

#computerscience
#physics
#art
#biology
#nature
#meme
#comedy

And you're using the same tags over and over again, regardless of the content.

Could I ask you not to do that?

Mastodon doesn't have a meaningful search facility and relies on tags being semantically meaningful.

Tags work best when they are targetted. They help people find the content they're looking for, otherwise they have the flavour of spam.

Thanks.

I have no idea what this question is asking for: ...

2026-01-16T09:46:23Z

I have no idea what this question is asking for:

https://f.cz/@xChaos/115904069494172138

Natural language is not good for precise specifications, which is exactly why we have mathematical notation and computer programming languages, and why good specifications have multiple, well-chosen examples.

Something our minister said yesterday made me look up a ...

2026-01-12T14:07:57Z

Something our minister said yesterday made me look up a quotation, and once again, "AI" shows just how reliable it is. With a stray "W" in the quotation it gets attributed to one writer, and without it the quotation gets attributed to someone else entirely.

Don't. Trust. "AI".

"I once absent-mindedly ordered Three Mile Island dressing in ...

2026-01-08T09:30:03Z

"I once absent-mindedly ordered Three Mile Island dressing in a restaurant and, with great presence of mind, they brought Thousand Island Dressing and a bottle of chilli sauce." -- Terry Pratchett

HAPPY PERIHELION !! Less often celebrated, here we are at our ...

2026-01-03T17:34:18Z

HAPPY PERIHELION !!

Less often celebrated, here we are at our closest point to the Sun and travelling at the highest speed in our orbit.

So Happy Perihelion everyone!

"Raise your words, not voice. It is rain that grows flowers, ...

2026-01-02T09:30:03Z

"Raise your words, not voice. It is rain that grows flowers, not thunder." -- Jalal ad-Din Muhammad Rumi

For everyone, whether you celebrate Christmas or not ... HAPPY ...

2025-12-25T14:10:45Z

For everyone, whether you celebrate Christmas or not ...

HAPPY SOLSTHELION !!

You also need the observation that no element is its own inverse, ...

2025-12-24T14:40:03Z

In reply to nevent1q…0pna
_________________________

You also need the observation that no element is its own inverse, which isn't hard, but needs to be mentioned.

Going with "al-Haytham's theorem" seems to be the best version so far, even if it is naming it after a person, and is therefore non-descriptive.

This is a tricky problem, and there may be more pressing issues around. Even so, although naming things is hard, I think it's at least important to think about it.

Never totally comfortable mixing the name of a theorem with its ...

2025-12-24T13:47:25Z

In reply to nevent1q…2uaf
_________________________

Never totally comfortable mixing the name of a theorem with its method of proof.

I never did this theorem in my course work, I knew and quoted the result for quite some time, and one day I realised for myself why it was true.

I feel like the name of a theorem should be about the result, not the proof. After all, there might be a completely different proof.

(But I do love how it drops out of the pairing)

What would be a nice, clear, reasonably descriptive name for this ...

2025-12-24T12:31:31Z

In reply to nevent1q…dyja
_________________________

What would be a nice, clear, reasonably descriptive name for this theorem?

Given an integer n>1,

$ (n-1)! \equiv -1 \pmod n $

$ \iff $

n is prime.

3/n