ocfnash

According to http://madrona.ca/e/coremem/index.html

> I have seen it [core memory] in service as recently as 2004 in a telephony control application

Thank you for sharing these memories.

I'd be very interested to hear any thoughts you might have about Jung Chang's book "Wild Swans".

I read this book a year or two ago and learned a lot from it, but I also learned that many people who grew up in China take issue with the author's account. I'd be grateful for any remarks you may be able to share.

Mathlib Initiative | DevOps Engineer | Fully-remote | Full-time

The Mathlib Initiative is a new programme of Renaissance Philanthropy. We exist to support Lean's open-source library of formal mathematics known as Mathlib https://leanprover-community.github.io/

Please apply directly at: https://www.renaissancephilanthropy.org/careers/devops-engin...

Most viruses are bacteriophages, so I imagine bacteria would run wild!

According to the 6/N from this series, they are claiming full marks for problems 1 -- 5

https://x.com/alexwei_/status/1946477742855532918

I'm a bit surprised nobody seems to have mentioned http://fixyt.com

I have a bookmarklet:

javascript:(function() {window.location=window.location.toString().replace(/^https:\/\/www.youtube\./,'http://fixyt.');})()

and whenever I want to watch a YouTube video, I just click that and enjoy an ad-free experience.

I think it is worth comparing this problem with the question of the behaviour of a particle placed at the apex of a cone. I claim it is clear that in this case, the problem is clearly not well-posed because the apex is a singular point: the slope at the apex is undefined. The singular nature of the slope (first derivative) is the issue.

This "dome" is essentially the same issue just with the singularity buried one level deeper: you need to take second derivatives to see it. Indeed a planar cross section containing the vertical axis through its center is a graph of the equation $y^2 = |x|^3$ (up to constants) and this is not twice differentiable at $x = y = 0$. Newtonian mechanics is governed by a second order differential equation, so we need a C^2 regularity assumption to get uniqueness.

So for me there is not really any more philosophically interesting than the question about a particle balancing at the apex of a cone.

If you like these, you should try the Uncle Fred books. Of course almost everything by Wodehouse is a sublime masterpiece.

As a kid, the alliterative mnemonic we were taught was "current kills".

The computer did find the answers itself. I.e., it found "even integers" for P1, "{1,1}" for P2, and "2" for P6. It then also provided provided a Lean proof in each case.

If you are curious, I encourage you to look up The Sphere Eversion Project [1].

It was a project in which we formalised a version of Gromov's (open, ample) h-principle for first order differential relations. Part of the reason it was carried out was to demonstrate what is involved formalising something in differential topology.

1. https://leanprover-community.github.io/sphere-eversion/

You can see Klein's work in action in Python here if you're interested:

https://github.com/ocfnash/icosahedral_quintic

You can even follow his progress on GitHub here:

https://github.com/teorth/symmetric_project/

Note that this argument does not depend on the fact that the blue rectangle also has equal area.

This argument thus teaches us even more, namely: the configuration of the four equal-area rectangles orange, yellow, green, pink has the special property that if you widen it to get a square, the extra piece you add also has equal area.

I salute your intention to find the silver lining but my experience reading patents is that they are hard to read. I believe this is because their job is not to convey information but rather to fulfill a legal requirement. I also believe that less restriction of these "inventions" would lead to a greater proliferation of truly useful explanations. No doubt there are exceptions but this has been my experience.

I've been using fixyt.com to avoid YouTube grossness for years. Thanks to the bookmarklet below, whenever I land at youtube.com I'm only ever a click away from escaping their awful, awful app.

javascript:(function() {window.location=window.location.toString().replace(/^https:\/\/www.youtube\./,'http://fixyt.');})()

A couple of years ago I read Irving Stone's biography of Van Gogh [1] and it very much enriched my experience of Van Gogh's art.

The book is based largely on a collection of letters between Vincent and his brother Theo and is quite moving sometimes.

I recommend it!

[1] https://en.wikipedia.org/wiki/Lust_for_Life_(novel)

Presumably one could now punish this behaviour by spamming the API with a firehose of fake data?

I note that this also appeared just days ago: https://www.irishtimes.com/business/2023/05/15/three-quarter...

I'm not quite sure what conclusions to draw.

The date of the last person executed by guillotine in France is surprisingly recent.

I mentioned this in a reply to a comment below but I think it is worth repeating at top level: there is a great app called Pytch which is a bridge between Scratch and Python (and runs in a web browser).

I always recommend it to anyone teaching young kids to program.

You can find it here: https://www.pytch.org/app/

There is a marvelous app designed to solve exactly this problem called Pytch: https://www.pytch.org/app/

It's not especially relevant but I can't help being reminded of VerizonMath https://www.youtube.com/watch?v=MShv_74FNWU

Weirdly, I was just sent this same blog post a few days ago. I guess it’s doing the rounds. I’ll repeat what I said to my friend who sent it.

Ramanujan was of course an extremely talented mathematician but IMHO, there is an unnecessary cult of mystery about him. In particular, there is no mystery as to where this formula comes from: it is obtained from applying a standard technique to a standard formula. Also, it is just one instance, I’ll call it the “k = 6” instance, of a family of such formulae and I’m near-certain the “k = 2” case was known before Ramanujan (on phone or would double check).

In any case, the standard formula is just the series expansion for: n! / sqrt{2πn} (n/e)^n and the standard technique is to raise both sides of a series expansion to some power, k say, multiply out one side, and then take k-th roots again.

In this case we just need to calculate: (1 + 1/12n + 1/288n^2 - 139/51840n^3 + O(1/n^4))^6 = 1 + 1/2n + 1/8n^2 + 1/240n^3 + O(1/n^4)

After taking the 6th root again we multiply inside by 8n^3 (from the LHS) and you get Ramanujan’s formula.

Assuming it is accurate, the final sentence in this article is especially notable.

I expect that the comment above was referring to the negative externalities, not captured by the financial side.

For example, having more free time is probably not adequate compensation for the greenhouse gases emitted (at the societal level at least).