Academia in 2018: trying to remember if a site is one of those skeezy content aggregators or a real journal publisher's necessarily-generic name for their online offering.

Today's conventions and concepts question: does a 0×0 matrix exist? How about 0×m? If yes to both, are they different objects? (Interpret 'does' and 'exist' as you wish)

Compound interest at 2% is about twice as quick to double your investment as compound interest at 1%.
5% is about 5 times as quick.

But not exactly! 10% is only about 9.5 times as quick.

Does this count as a rule of thumb?

I've added my pronouns to my profile, using pronoun.is. Not sure if it's any more immediately comprehensible than just "he/his", but at least it's clickable

307. THE COLOURED COUNTERS. The diagram represents twenty-five coloured counters, Red, Blue, Yellow,
Orange, and Green (indicated by their initials), and there are five of each colour, numbered 1, 2, 3, 4, and 5. The problem is so to place them in a square that neither colour nor number shall be found repeated in any one of the five rows, five columns, and two diagonals. Can you so rearrange them?

What do you call it when somebody's kink is dressing up like trigonometric functions? Show more

Fancy some lunchtime turbonerdery? Play MatchTheNet, where you have to match 3d polytopes to their nets: matchthenet.de/ mathstodon.xyz/media/-I3nAy8m4

I've just seen the first couple of spam accounts on mathstodon.xyz. I hope this doesn't become a thing.

(It will.)

Politics are like an accent: if you think someone hasn't got any, it just means they share yours.

AAAAH

So we always go to the doggy park around sunset - there are loads of huge trees there and the sun is always twinkling through them with lovely Golden Hour light so I figured tonight I'd try for some sunbursts - you need a high F-Stop but compensated with slow shutter speed and/or high ISO, and careful positioning, and it can be tricky.

So I'm fracking stoked that I got this DOUBLE SUNBURST. AAAAH

#photography

photog.social/media/M4T2jOMC1c

Okay I barely understand this, but it's kinda cool: Turing-complete computing by links and rotary joints

arxiv.org/abs/1801.03534

You won't regret clicking around this birdsite thread on influential women in web dev and the lack of credit they receive for their work. twitter.com/jensimmons/status/

You'll like this, @icecolbeveridge: Tim Gowers on learning mathematical French by immersion plus.google.com/+TimothyGowers

"Legends of the Ancient Web" idlewords.com/talks/ancient_we

Another sobering talk from Maciej Ceglowski. He's shaping up to be a good candidate for "conscience of the tech industry."

Prompted by a stupid tweet by QI on twitter ("If the 5 trillion spiders in the Netherlands took to eating humans rather than insects, they’d consume all Dutch people in just three days." - twitter.com/qikipedia/status/9), I reckon that it'd take the UK's window cleaners 2.5 months to cover the distance to the moon if they did that instead of climbing ladders

Any other Mathstonautes going to the Joint Math Meetings in San Diego?

Huh! So the first known written reference to meat between bread as a "Sandwich" is in a 1762 entry in Edward Gibbon's diary.

A Mastodon instance for maths people. The kind of people who make $\pi z^2 \times a$ jokes.
Use $ and $ for inline LaTeX, and $ and $ for display mode.