https://twitter.com/Foone/status/1151654951203958785

<< I'd had a tab open with a bunch of text for about 6 hours and I've been meaning to read it and I haven't yet.

the best part? it's about ADHD and how it stops you from doing things. >>

A formula for designing lenses with no spherical aberration: https://petapixel.com/2019/07/05/goodbye-aberration-physicist-solves-2000-year-old-optical-problem/

This seems to have little practical value as there was already a numerical solution, and I don't think it handles chromatic aberration, but it's interesting that there is an analytic formula for these shapes.

@phooky @qrs it is chained to a piece of Amsterdam's street furniture, a pole to block cars. Well, you can't ride away on this bike, so it's OK for a short stop at broad daylight in Amsterdam. Less so for a longer one, but well, the bike is crap...

https://nl.wikipedia.org/wiki/Vlag_van_Amsterdam

@ccppurcell bra-ket is more or less a Hermitean scalar product, IIRC. Nothing needs to be invented there.

@ccppurcell bra-ket was always there in quantum physics, I just wish physicists made an effort to avoid it to be understood by mathematicians

Turkey has charged over 700 academics with terrorism for signing a peace petition: https://www.insidehighered.com/news/2019/07/01/about-700-academics-have-been-criminally-charged-turkey-their-signatures-petition

Among the most severely penalized among them is Tuna Altınel, a mathematician in France who was arrested visiting family in Turkey, and who has now been imprisoned for over 50 days. For more see http://math.univ-lyon1.fr/SoutienTunaAltinel/?lang=en (via https://cameroncounts.wordpress.com/2019/05/31/tuna-altnel/)

@ccppurcell well, double vs single pair of brackets is nothing unsual, one e.g. does \(k[[x]]\) for the ring of formal power series in \(x\) over \(k\)

@ccppurcell @jsiehler the usual notation for k-subsets of S is \(\binomial{S}{k}\).

For multisets, add extra pair of (), see https://tex.stackexchange.com/questions/5816/multiset-notation-in-latex

Mathematics, historical nazis Show more

NEW: U.S. political operative Paul Manafort received payments for consulting work in Ukraine through over a dozen shell companies thanks to veteran Cypriot lawyer Kypros Chrysostomides, known by some as “Dr. K.”

https://www.occrp.org/en/investigations/the-curious-case-of-dr-k-and-mr-chrysostomides

The slope number of a graph G is the minimum number of distinct gradients of the edges in a straight line drawing of G.

An open problem that is very nice in my opinion: When Δ(G)≤3 the slope number of G is at most 4. For any k there is a graph G with Δ(G)=5 and slope number >k. But what about Δ(G)=4?

Not really my area at all but I like questions like this: where's the boundary?

> We shouldn't be applauding developers like Tusky or Funkwhale when they block Gab. We shouldn't be surprised when decent people do decent things. This should be expected. It's when it doesn't happen that we should be outraged.

You nailed it.

The fact we had to make this statement and received so much visibility and sincere "thank you!" replies from it makes me ashamed, on so many levels…

We're basically gaining traction and attention *because* the current situation is bad. Even the slightest move in the opposite direction feels like an incredible improvement.

This is fucked up.

@thomasfuchs fancy COBOL? Enjoy e.g. https://youtu.be/vLlJxw76qcs

@loke is the IT skills shortage getting worse in SG in the past 5 years? Just curious...

20 Hours, $18, and 11M Passwords Cracked

HN discussion: https://news.ycombinator.com/item?id=20276438

https://hackernoon.com/20-hours-18-and-11-million-passwords-cracked-c4513f61fdb1

Joined Feb 2019