rnather @rnather@mathstodon.xyz

Mathematics is like checkers in being suitable for the young, not too difficult, amusing, and without peril to the state. -- Plato

I see so much uninformed opinion dressed up and pretending to be objective analysis. Please, do not do that.

UNIX-Prominenz wählte Schach-Eröffnung: 39 Jahre alte BSD-Passwörter geknackt www.heise.de/newsticker/meldun… #BSD #Geschichte #Hash-Funktion #Passwörter #Unix

New math post on my blog: Incenters of chocolate-iced cakes https://blog.plover.com/math/cake.html

So I'm sure you're all familiar with the UN projection of the Earth that puts the Arctic at the center and shows all the land, but let me present to you the inverse of that, the Spilhaus projection, which centers the map on Antarctica and shows the world's ocean as the single, continuous mass of water that it is.

here's an excellent picture to illustrate

these cars both appear black. but under sunlight one of them is actually red. they both appear black because the sodium vapour lamps that they're being illuminated emit light at a very narrow range of wavelengths, and it just so happens that the red pigment on the car absorbs those wavelengths. even though orange is traditionally considered a "combination of red and green", this kind of orange causes a red object to appear black. ain't that cool?

Give someone a program, you frustrate them for a day; teach them how to program, you frustrate them for a lifetime. -- David Leinweber

To ask is a temporary shame, not to ask a life-long shame -- Japanese proverb

I still find it faintly incredible that no group of scientists has gotten together and just made a damn set of free textbooks to cover the whole standard curriculum of their field. For uni physics, you'd need, roughly speaking and allowing for bits of overlap:

1. Classical mechanics
2. Single-variable calculus
3. Electromagnetism
4. Multivariable and vector calculus
5. Statistical physics
6. Quantum physics
7. Special relativity
8. Data analysis (a text most likely used as reference in a lab course)
9. Differential equations
10. Linear algebra

Education reform went haring off into MOOCs without really contemplating the possibility of making better resources for more traditional in-person teaching.

"i could give you this one now, or I could give you two of these if you wait"

oh you have to go get the other one?

"no, you just have to wait for it"

so you have the both right now

"yes and I'll give you one now, or--"

but you could just give me them both now if you wanted to

"i mean yes but--"

but instead you want me to sit here thinking about you arbitrarily not giving me both

"it will let me learn something about you"

yes, it's very clearly me we're learning something about right now

~ Reading about Alan Turing ~

*Sigh* I hope someday I'm so powerfully gay that it's a national security threat

I hereby announce this shop is clopen!

My God, It’s Full of Dots!
http://bit-player.org/2019/my-god-its-full-of-dots

Brian Hayes plays with the fractal circle packings of the plane (or of a region of the plane) that you get from a greedy process of picking random points and using either the maximum radius possible or the next radius on a given sequence of radii (but then only adding a circle if that radius fits).

Comrade @lapis just made me think about how in Spanish to say that you speak it well enough you say "me defiendo bien", literally "I can defend myself well", as if foreigners were going to attack you in another language and you had to quickly mount linguistic fortifications to fend them off.

A circle can thus be used to provide compartmentalization, kinda like module boundaries in Rust.

Can a circle sit on the edge of a circle and define a new branch of contexts? Possibly.

From this compartmentalization follows that there probably need to be an expression / glyph for exporting names to an outer circle.

And there obviously needs to be an expression / glyph for defining names in the first place.

@InspectorCaracal Thor's home Bilskirnor with 540 rooms? Tardis

Frey's ship Skidbladnir, that can fold up small enough to fit in a pocket? Definitely Tardis

That cryptic monad structure in Haskell that allows you to do occult tricks that lets you react to events forwards and backwards in time? Actually called Tardis.

(Yeah, the Haskell people built a fucking tardis, because monads)

What is the smallest prime?
Article by Chris K. Caldwell and Yeng Xiong
In collections: Easily explained, History, Notation and conventions, Integerology
What is the first prime? It seems that the number two should be the obvious answer, and today it is, but it was not always so. There were times when and mathematicians for whom the...
URL: http://arxiv.org/abs/1209.2007v2
PDF: http://arxiv.org/pdf/1209.2007v2
Entry: http://read.somethingorotherwhatever.com/entry/Whatisthesmallestprime

Here's a closeup of the handwriting one. I wandered round the department knocking on doors, asking people to write some mathematical notation. It was fascinating seeing the different symbols and conventions used in different disciplines.
What can you spot in this snippet?

privacy is your local scope where you perform your local reasoning

maybe people who don't think privacy is important are okay with programming by only mutating global variables