Vlad Tenev tweeted about it here: https://x.com/vladtenev/status/1994922827208663383
Readit Newsareyousure commented on Asymptotically optimal approximate Hadamard matrices arxiv.org/abs/2511.14653... · Posted by u/mathfan
Very cool! This is one of the more impressive "AI does math" writeups I have seen.
In case anyone is curious, there is a discussion of AI in Section 5 (page 8 of the PDF). This direct link might work: https://arxiv.org/pdf/2511.14653#page=8
areyousure commented on Over-regulation is doubling the cost rein.pk/over-regulation-i... · Posted by u/bilsbie
It’s quite possible that the pollution controls on some of those engines wig out and turn the truck into a coal roller. Even with 10-100x fuel efficiency improvements, it could increase particulates, etc due to a bad fuel mix.
The real question is why they’re paying $100K per truck for a mobile smog test rig.
The test equipment can’t possibly cost more than $100K. That leaves $26.9M of “you’re doing something obviously wrong”.
My guess is that the regulations aren’t actually forcing the idiocy, or they are designed to subsidize emissions testers in some way. I’d guess it is the latter, which is just bad regulation.
Smog checks in California have been pretty poorly administered for years. For one of my cars, the lowered the nox standard until it would have failed fresh from the factory, then made me spend more than the car was worth on a special cat that reduced emissions by < 10%.
These days, cars continuously smog check themselves, so there could be a mandatory “send smog check report to the state” button on the dash, but that’d stop the gravy train for the smog test operators. At least they don’t make you smog test EVs, I guess.
With all the money that’s wasted on having stations that check dashboard error lights, they could install air and noise pollution monitoring sensors, and seize cars that have been modified to be non-street-legal. This would be stronger and better regulation than we currently have (less disruption to people obeying it, more bad cars taken off the road, minimal privacy implications for anyone in compliance with the law, and lower cost to enforce).
Also, it’d eliminate the need for the startup to test their truck retrofit, since the trucks would just light the stations up like a Christmas tree if there was an actual problem.
> The real question is why they’re paying $100K per truck
> The test equipment can’t possibly cost more than $100K. That leaves $26.9M of “you’re doing something obviously wrong”.
It seems clear from the original text ("It costs $100,000 per certification") that it's the certification FEE that is $100k. For example, https://ww2.arb.ca.gov/sites/default/files/2024-08/mac202403... includes an individual base fee of $126,358.
areyousure commented on Margin debt surges to record high advisorperspectives.com/d... · Posted by u/pera
> Or you could recognize that "essential" has a meaning in economic/financial terms
I do not recognize that. That is the point of my argument. A large portion of economics is rich people trying to justify their own greed as being moral. Classifying goods as "essential" vs. "non-essential" is a way of telling poor people what they're allowed to have, and always has been. A good goes from "non-essential" to "essential" only when rich people are worried they'll get guillotined if the poor don't have access to it.
I'm aware that it has a definition in terms of what people are able to stop purchasing when their income goes down, or how consumption relates to income levels in general, but the former is a problematic definition for many reasons, and the latter does not actually coincide particularly well with the categories of goods people list off when they think of "essential goods". Humans in real life just don't respond to changing conditions the same way the little econs in your head do; they way you've decided they "should".
Ever heard that humans don't "behave logically"? Yeah, that's economists with overly simplified models being annoyed that (mostly) poor people don't act the way that they've decided poor people should act. See the trend?
Ask four economists write out a list of "essential goods" and you'll get five different lists. That is not how definitions work. Ask four mathematicians whether something is a Commutative Ring or not and they'll all agree. That's a definition. "Essential" does not have a definition. Its meaning shifts depending on which group the author of the Wall Street Journal op-ed you're reading wants to villainize this time.
> Ask four mathematicians whether something is a Commutative Ring or not and they'll all agree.
Amusingly, there are at least 3 different definitions of commutative ring.
The principal issue is whether it must have a 1 (unity, ie a multiplicative inverse). Wikipedia https://en.wikipedia.org/wiki/Commutative_ring as well as most modern sources insist on this.
Britannica https://www.britannica.com/science/ring-mathematics#ref89421... as well as many older sources (such as Noether's original definition and van der Waerden) do not insist that the ring have a 1. Even first-edition Bourbaki didn't have 1!
Finally, if you do have a 1, then sometimes people include the condition that 0 != 1, ie the trivial/zero ring is deemed not a [commutative] ring. This is somewhat hard to find, but is relatively common among people who specifically define the concept of "ring with identity" (eg Zariski+Samuel). I have also found it unqualified (ie, just in the definition of "commutative ring") in the wild, eg in "Handbook of Mathematical Logic" by Barwise or "The Math You Need" by Mack.
(I agree with people like Conrad and Poonen that rings should have a 1. And I guess that the zero ring is in fact a [commutative] ring.)
To the ancients, as already clearly expressed by Aristotle, natural numbers and real numbers were both quantities. Quantities were classified in discrete quantities, of which natural numbers are an example and continuous quantities, of which real numbers are an example. This classification remains completely valid today.
The ancient mathematicians and philosophers were using the word "quantity" in most contexts where modern people use the word "number", i.e. when the word is applied to different kinds of "numbers", not just to natural numbers.
There is no difference in thinking between ancients and moderns, it is just a difference in the words that happen to be used.
Both the similarities and the differences between natural numbers and real numbers are well entrenched in most natural human languages since many millennia ago, before any scientific theory of quantities, numbers and magnitudes, as exemplified by the similarities and differences between questions like "How many ... do you have?" and "How much ... do you have?".
Actually I consider the ancient usage of the words as more sound than the modern usage. There appears little justification for the modern usage of the word "number" instead of the previous usage of "quantity", except that "number" is a shorter word than "quantity", so the change in terminology is just due to laziness, not to any theoretical reason. However what has been gained by saying "number" instead of "quantity" when the wider sense is intended, has been lost due to the requirement for qualifying "number" as "natural", "real", "integer" etc., when the narrower meaning is intended.
Etymologically, "number" is the result of counting, which real numbers and many other kinds of "numbers" that correspond to continuous quantities are not.
Suppose we designate a unit line segment, and from that we pick out a line segment of (what we now call) length 2 and separately a rectangle of area 3. To "an ancient" (like Aristotle), does it make sense to add the length and the area to get 5? If you then drew a line segment of length 5, would they say it has the same magnitude?
(My understanding is "no" to both questions.)
areyousure commented on TSMC expected to announce $100B investment in U.S. wsj.com/tech/trump-chip-m... · Posted by u/perihelions
>US already trashed the Budapest memorandum that it signed in 1996. We were supposed to provide security to Ukraine in exchange for them giving up nukes.
This is a common misconception. If you read the memorandum (it's rather short) you'll see it isn't true. We only promised to seek UN Security Council action. We went far beyond that.
https://treaties.un.org/doc/Publication/UNTS/Volume%203007/P...
You are correct that the Memorandum is rather short.
The promise to seek UN Security Council action is only in case Ukraine is attacked with nuclear weapons.
areyousure commented on The New York Stock Exchange plans to launch NYSE Texas ir.theice.com/press/news-... · Posted by u/ChrisArchitect
Odd lots don't contribute to the NBBO, and placing an order for an odd lot doesn't have to execute within the NBBO. (People can trade "past" you, I am pretty sure ISO's don't need to clear you, etc). (Note these are rules for market participants, not retail customers). So for a firm trying to argue they provide excellent price improvement and execution efficiency for their customers, they can't "just" send the orders to the lits.
And even if they could "just" do so, internal matching typically provides better price improvement on the NBBO than even the best execution you could get off the lits.
Edit: But yes TBC, you're correct that odd lot trades aren't unusual. But you're seeing trades there by actual market participants, not retail orders. They're not just trying to get those 2 shares, there's a broader strategy and they're aware of all the above nitty gritty.
Sadly, firms abuse odd lot rules to give people terrible prices: https://academiccommons.columbia.edu/doi/10.7916/2y01-1s13/d...
In example 3, the NBBO for stock ABC is 495--500, but there is also an odd lot offer for 497 on exchange. If a Robinhood customer sends a market buy order, then Citadel is allowed to fill it for 499.999 even though it's better to send to the exchange. (And if they then pick up the odd lot themselves, it's easy arbitrage.)
By the way, while you're correct about some of your claims, odd lot executions definitely have to occur within the NBBO. (How could it be otherwise?) Otherwise, in the example above, Citadel would give an even worse price!
areyousure commented on The New York Stock Exchange plans to launch NYSE Texas ir.theice.com/press/news-... · Posted by u/ChrisArchitect
Exchange trading happens in round lots that are usually 100 shares.
This is pretty much just a legacy thing, but so many technical systems have this assumption built in that while odd-lot trading (trades not in the round lot size) has become a little more common on the exchanges, it’s still treated weirdly by the various systems involved.
But also, it’s better for you as a retail investor, to get them from a middleman, because they will generally give you a better price than the exchange. They will give you a better price because retail traders tend on average to be worse at trading than the overall market. You should take advantage of that, regardless of your actual ability level.
My research suggests that the majority of on-exchange trades are odd lots.
For stocks like SPY (those over $500 per share!), the vast majority of orders are odd lots.
This article is many years old and already has data strongly in that direction: https://www.nasdaq.com/articles/odd-facts-about-odd-lots-202...
areyousure commented on The New York Stock Exchange plans to launch NYSE Texas ir.theice.com/press/news-... · Posted by u/ChrisArchitect
Just for the record, the latency arb / microwave networks speed game is basically dead as of 2018-2021. Looks at Virtu, formerly classic examples of the trade and now almost entirely "switched sides" and doing order execution services for the same big banks whose lunch they were formerly eating.
Furthermore, the wireless stuff is commoditized at this point. You can just rent to be on the wireless that Apsara (et al) offer, and while some have private networks, there's not enough money left in the trade (see above) to be worth it if you don't already have one.
This is combined with liquidity moving away from public exchanges (both the lits and darks) towards being matched internally/by a partner (PFOF matching), which is purely a win for retail traders and is its own force that isn't going away. (Go on robinhood and buy 2 shares of SPY. It fills instantly. People love that. You can't just go get 2 shares of SPY off the lits, so where dyou think those are coming from?)
Traditional HFT is dead. The only extent any of the firms are still alive is the extent to which they've moved on to other trades, many of which are so much less latency sensitive that the microwave edge doesn't really give you enough alpha to be worth it.
(I worked for a firm for a long time that didnt move on to other trades... so I'm quite familiar with the scene.)
> You can't just go get 2 shares of SPY off the lits, so where dyou think those are coming from?
Why can't you just get 2 shares on an exchange?
As a more substantive comment: You may find the thesis "Propagation networks : a flexible and expressive substrate for computation" by Alexey Radul interesting. https://dspace.mit.edu/handle/1721.1/54635