evanpw (u/evanpw) - Readit News

evanpw commented on Elusive ‘Einstein’ solves a longstanding math problem nytimes.com/2023/03/28/sc... · Posted by u/crazydoggers

jeffparsons · 2 years ago

> In my book, this means it is rather using two tiles than one.

I expected to see more about this. Are a given 2D shape and its mirror image generally considered the same shape by... the people who study this stuff? That would surprise me. So much so that calling this an "aperiodic monotile" doesn't feel right.

evanpw · 2 years ago

Yes, "same shape" in this context means "isometric". Rotations and reflections are considered differences in the way the shape is placed into the plane, not differences in the shape itself.

evanpw commented on NYSE Tuesday opening mayhem traced to a staffer who left a backup system running bloomberg.com/news/articl... · Posted by u/helsinkiandrew

herpderperator · 3 years ago

If the trades are being cancelled, are they going to correct the chart data? Right now it looks very misleading on the daily[0], weekly, monthly, quarterly, yearly etc for large caps that trade quite steadily otherwise. I do understand that this would be a challenging effort as that data already flowed to and was stored by all the broker-dealers, but I think it should be done.

[0] https://www.dropbox.com/s/6jdmgkdyei9xqz0/mcd.png?dl=0

evanpw · 3 years ago

The same feed that publishes trades also publishes trade busts, so it's up to whoever's consuming it downstream to take care of.

evanpw commented on NYSE Tuesday opening mayhem traced to a staffer who left a backup system running bloomberg.com/news/articl... · Posted by u/helsinkiandrew

WiSaGaN · 3 years ago

I don't know what happened in current case. In the Knight Capital case, KC clearly didn't intend to send those erroneous orders. And if those trades were not annuled, KC would not be able to settle those, since the trade loss were larger than the collateral KC put up.

evanpw · 3 years ago

The trades were not annulled, because NYSE ruled them not "clearly erroneous". Which is why it is was an existential mistake, not just an embarrassing one.

evanpw commented on Games people play with cash flow commoncog.com/cash-flow-g... · Posted by u/simonebrunozzi

wodenokoto · 3 years ago

During my college course on accounting cash flow was by far the most difficult to understand and I still find it difficult in light of the cable company example.

As an owner you still want money to spend. How do you get that if not from the profits?

evanpw · 3 years ago

I had the same question while reading. It's probably obvious to the startup crowd, which is why it wasn't made explicit, but I think the trick is this: a company which will never make a profit is (should be) worth zero, but a company that has the ability to make a profit in the future is valuable, even if current profits are zero. So rather than making a profit and paying it to yourself, it's better to make the company as valuable as possible to other people by reinvesting everything, and then sell stock or borrow against it for your own consumption. That definitely seems true for the most prominent outliers, but no idea whether it's actually true for the average or median owner / founder.

I guess this why EBITDA is important: if you have positive EBITDA and stop growing the business, you can pay off your loans, finish depreciating your existing equipment, and with I=D=0 you have real profits.

evanpw commented on Ask HN: Concepts that clicked only years after you first encountered them? · Posted by u/luuuzeta

evanpw · 3 years ago

This is true of almost everything in math. You learn some definitions and techniques in one class, and it doesn't all become clear what's going on until you've used those to as the base layer for solving some other problems in the next class. Part of it is just that it's hard to teach you need the first concept in order to understand the second, but you need the second to understand why you should care about the first, so it's all a bit circular.

evanpw commented on Supreme Court limits EPA’s power to cut emissions bbc.com/news/science-envi... · Posted by u/ComputerGuru

rayiner · 3 years ago

Headlines about Supreme Court cases are almost uniformly misleading, because they suggest the Court is making decisions on policy issues rather than legal issues.

The very first words of the opinion, on p. 2, make clear that the legal issue before the Court is very different: https://www.supremecourt.gov/opinions/21pdf/20-1530_n758.pdf

The Clean Air Act does not purport to give the EPA blanket regulatory authority over anything involving emissions into the air. It has detailed provisions focused on reducing the amount of toxic pollutants, in particular through the use of control (scrubbing) technologies. This case concerns whether the EPA can use its power to impose control technologies on power plants, to force the industry to use a particular mix of power generation sources (solar, gas, etc.). The Court decided that the statute did not confer on the EPA the power to do that. The relevant discussion begins on page 16.

This decision gives legs to something that has been called the "major questions doctrine." The gist of that doctrine is that an agency can't stretch some pre-existing grant of Congressional authority to create sweeping regulations addressing a major new problem. As applied here, that means that the EPA can't rely on authority delegated by Congress to, for example, tell coal plants what kind of scrubbers they have to use, to tackle climate change. pp. 17-19.

evanpw · 3 years ago

> Headlines about Supreme Court cases are almost uniformly misleading, because they suggest the Court is making decisions on policy issues rather than legal issues.

I agree with this completely, but it doesn't help when justices begin their opinion / concurrence / dissent with a long policy discussion before talking about the legal questions. That's been the case in several of the recent decisions.

evanpw commented on Supreme Court limits EPA’s power to cut emissions bbc.com/news/science-envi... · Posted by u/ComputerGuru

nostromo · 3 years ago

> this court will reduce the Federal government to a non-entity very soon

This is an absurd take. All Congress needs to do is clarify that they’d like the EPA to regulate carbon emissions. That’s it. The laws regarding pollution control, many of which date back to the 1950s and 1960s, we’re not written with global warming in mind. So the court is saying the EPA needs to get permission from elected officials to regulate carbon.

evanpw · 3 years ago

That's not it at all. All parties agreed that Congress passed a law allowing the EPA to regular carbon emissions by setting emission limits on different types of power plants based on the best current technology available for emission reduction. The disagreement is whether that allows the EPA to set emission limits which are impossible to achieve, with the goal of forcing fossil fuel plants to shut down or subsidize renewable sources.

I encourage all the tech people around here to "read the code": https://www.supremecourt.gov/opinions/21pdf/20-1530_n758.pdf

evanpw commented on Why does science news suck so much? backreaction.blogspot.com... · Posted by u/sohkamyung

spaetzleesser · 3 years ago

How do they finance themselves?

evanpw · 3 years ago

A finance billionaire with a background in math and physics (Jim Simons)