Here are some books that I suggest to learn DSA properly:
1. A Common-Sense Guide to Data Structure and Algorithms from PragProg Bookshelf. Written in a very approachable manner with very good code. The best for self-learners.
2. Algorithms by Dasgupta, Papadimitriou, Vazirani (DPV). Very short and concise book- extremely well-written with a personality. Requires basic CS math.
3. Algorithm Design Manual by Skeina. Extremely approachable as well. Has 'battle stories' of algorithm usage. Good for self-learners. Links to problems in Leetcode is given.
4. CLRS is of course nice for a mathematically rigorous study.
Not a very good article at all. I'm beginning to consider calling it the 'Non-Scientific American' magazine.
So tell me what causes lift when there is a zero angle-of-attack? If it's not Bernoulli's Principle?
There are TWO causes of lift: both Bernoulli's Principle AND a (limited) Angle of Attack. These combine arithmetically to produce lift. Engine power (thrust) produces speed of the wing through the air.
NOTE: Angle of Attack is measured against the relative air-flow. It has nothing to do with the angle of the wing relative to the ground.*
If the countering weight plus drag elements are less than the lift plus thrust elements the wing will fly. If the weight plus drag elements are greater than the lift plus thrust elements, the wing won't fly.
* Assume a powerful jet plane with engine-thrust greater than its own weight. That will allow it to climb vertically at 90 degrees to the ground. Assume the wings on that plane are fixed at zero degrees angle to the longitudinal axis of the plane.
Q: If the plane is climbing vertically (90 degrees), what is the angle of attack of the wings of that plane?
The younger generation may not be familiar with the name Thomas Friedman (NYT) as his popularity seemed to peak decades ago but he had this "McDonald's theory of no war" that people quoted:
>In Friedman’s hands, the sophisticated flavors of Cobden and Smith were homogenized into a quick-serve dish, which he called the “Golden Arches Theory of Conflict Prevention.” His thesis, originally expounded in a 1996 column, proposed to explain the decline in war as a result of the expansion of global capitalism: “No two countries that both have a McDonald’s have ever fought a war against each other.” -- from : https://archive.ph/lNwNQ
Moscow Russia has McDonald's. Kyiv Ukraine also has McDonald's. Well, here we are.
It will take you through the basics of the internet, HTTP, browsers, requests, cookies, databases, caching, hasing, passwords, by having you build a web application. Granted, it's on Google App Engine, but still, most of the router syntax out there is similar (webapp2 from web.py, similar to Flask, Tornado, and others).
You will learn a lot, and you'll see the result right in your browser by having a live web application. You can then take that knowledge and develop tools for yourself and others and put them online for all to access and use.
If you want to do it better and "leap-frog", read Brett Slatkin's "Effective Python: 90 Specific Ways to Write Better Python". This book will make you write code as if you had been coding for years... But, that's only doing it "right", you need something to do right in the first place: you've been in business, strategy, and operations, and you've been trained in mechanical engineering: I think you are in no shortage of ideas and things to code, so have a it.
You're in an excellent position of having been at the intersection of a bunch of cross pollinated fields, and you'll have a new skill to bring them together and do wonders. All the best!
It depends mainly on how much more money the homeowners believe they can fetch by listing the home versus selling it right away on the spot.
For example, if you're the homeowner and you think you can get, say, a few extra $100K's by listing your home instead of selling it right away on the spot, you would probably take your changes and list it. Even if you're under pressure to sell quickly, you might still try listing the home for a couple of months to see what happens. Only if you think your home is a lemon will you consider selling to Zillow.
That's why Zillow ended up buying all those lemons.
This is kind of it, vegetarian meat competes in the lips and assholes market. It tastes like meat to the same degree hot dogs taste like meat. It's probably even worse for you.
I'll just chime in and say I believe you are misinformed and wrong on this issue. I can say definitively that my firm which engages in HFT and all the other quant/HFT firms I know of have decided to stay clear of the meme stocks, ie. GME, BB, AMC, and a few others and I am not aware of any open secret that HFT firms are sneakily taking advantage of this situation.
Your statement that HFT firms think that retail traders have no clue what they're doing is a complete misrepresentation of the intention behind PFOF. It's not at all that we think retail traders are idiots, it's that retail orders are usually not coordinated and sustained activities the same way that institutional orders are. If an institution is buying and I sell into it, it is quite likely that the institution will continue buying more and more over a long period of time which increases the duration of my exposure to that institution's order flow. Furthermore it's unlikely that institutional order flow on the continuous market will balance out with other institutional order flow, since in situations where such an opportunity exists, brokers for said institutions will arrange for a block trade or use auctions instead of the continuous market. So trading against an institution means assuming exposure for an extended period of time.
With retail orders, usually a trader buys with a few orders in a way that's typically uncoordinated with other orders and that's it. I don't need to be worried that if I sell to a retail trader that a whole bunch of further traders will follow behind them in the same direction, increasing my exposure.
This is not to say that institutions know what they're doing and retail traders don't, or vice-versa. An institution may have no idea what they're doing and pissing their money away and I still won't want to trade against it simply because as an HFT firm my goal is to lock in a spread as quickly as possible as opposed to speculate on the long term prospects of a company. If anything, to the extent that there is an open secret in this industry, it's that institutions don't perform much better or have much of an advantage over anyone else. That said even if they did it wouldn't matter one way or another, what I care about is that the order flow that I am trading against can balance out over a short period of time so that I can lock in the spread.
It is precisely because retail traders are behaving in a coordinated manner on meme stocks that my firm and all the other ones I know about are not participating in them. Retail flow on meme stocks is often coordinated, at least implicitly so as an HFT firm you may risk holding a significant position for a long time, which is not ideal.
That said the market is very big and the meme stocks constitute but a tiny fraction of a fraction of the activity. It's not a particularly big deal one way or another.
It's kind of an open secret, but retail traders hopping onto meme stocks like DPZ and TSLA is, counterintuitively to an outsider, actually very profitable for HFTs and market makers.
A good example might be - imagine you are a car dealership, so serving as a rough approximation of a market maker. What kind of entities do you want to trade against? Other car dealerships (informed counterparties), or your average suburban minivan owner (uninformed counterparties)?
It's immediately obvious - the rationale is that when you trade against uninformed order flow, your measure of adverse selection is far lower than if you trade against informed order flow. Your average suburban minivan owner is going to be more time-sensitive and price-insensitive than another car dealership who is willing to look high and low for better deals.
Adverse selection, in this context, is that of the orders you're offering to the market, only the subset which have the greatest likelihood of immediately losing you money are selected. From the perspective of your counterparty, they will only lift your offer if they think it will make them an immediate unrealized profit. Keeping track of your adverse selection is an extremely important part of HFT - in fact, HFTers will try to identify informed vs uninformed order flow and only try to trade against the latter, to reduce immediate unrealized losses due to adverse selection.
This is why PFOF (payment for order flow) exists. It's because companies like Virtu think that traders on RobinHood have no clue what they're doing, and they [Virtu] can come in and eat all the alpha. Virtu doesn't frontrun RH orderflow - instead, they get what's called "first look" at the flow. They get to decide to either immediately fill the offer, or let it hit the real market. From the perspective of a RH user, this is really no harm, because whether Virtu trades against you, or your offer gets lifted against the broader market, doesn't really matter to you.
That website is tuned for SEO maximalism, every article, every title, all the keywords and even the affiliate links. Good example for anyone looking to build a good inbound content strategy.
>This is a function of a government conferred by the rights of being a citizen.
Woah, woah, woah. Hold up. Which jurisdiction?
Rights are not contingent on Citizenship in the United States. Rights are fundamentally inalienable. They are recognized to exist a priori to an established Government. This is exactly why the Founders wrote the Bill of Rights the way they did, because this is such a seductive way of thinking these things work, and the Tyrant relies on this failing of reasoning to provide the foundation upon which to build their beachhead. The only citizenship-contingent right, is the right to vote. That's it. You can still be represented and hound a Congressional representative as a non-citizen. You just can't participate in the political cluster we call a voting system run by a bipartisan political machine.
Even taxation is not an "exchange" for rights, but rather a concession to the legitimacy of the Government to organize it's affairs so as to be able to successfully do it's job as the Government. Taxes are "voluntary" in the sense that you are the one accepting the onus for being fully compliant. It just happens taxes happen to be an excellent way to strongarm people due to them being coupled to the immediate reality of what we can achieve in life.
Now, back to the topic at hand...
One other power vested in the Federal Congress is to put in place incentives for the furthering of the Arts and Sciences. It is under these auspices that Patents, Copyright, and other matters of Intellectual Property fall.
The controversy around it isn't the legitimacy thing of these things, but rather they've actually in practice incented the advancement of the Arts and Sciences in a world where IP is starting to dwarf actual physical property, and where the analogy to theft completely falls apart. As the world is only enrichened by the sharing of technical know-how, inspired by exposure to the Artist's work.
If you look at the state of progress of the Art's... You still have places like Disney milking old IP for all it's worth. The music industry arguably seems to spend more time trying to counter unfettered spread of the Artist's work than anything else. What of the Sciences? The problem there is access, and people being able to build up to the point they can even phrase the question never before asked. The thing that holds them back is the locking away of the fruits of human knowledge behind the facade of costly obstructions in the form of material duplication and the need to maintain "purity" through gatekeeping of the consumer. SciHub has arguably done more for the advancement of increased access of the layman to the best and brightest; all at no cost or detriment to the researchers in question.
Point being: government, or being subject to it's devices has very little to do with the essential nature of the problem. When duplication doesn't cost a bloody thing; why do we create and enforce, and incent artificial scarcity?
How does that further the Arts and Sciences? Until every man, woman, child, or otherwise is able to deliver novelty to the world without institutional roadblocks, or being harassed into not contributing; we still have an issue, in that our system does exactly that; it discourages innovation because the precondition of being able to deliver and profit is that you have to parse the IP landscape to ensure you aren't stepping on someone else.
Patents and such work for businesses where economic might through collectivization dwarf's the individual's ability to realize the implementation or rewards for having made their thing. They also create that perverse artificial scarcity previously mentioned.
Throw in a ruinously expensive nature of litigation and the legal system, and the oddities introduced through case law, and honestly? I'm not convinced all the trouble caused pays for itself by boosting innovation above the baseline human drive to create.
Anyway... Apologies. Got a bit carried away there.
"Our failure to understand [the Taliban's] dynamic has had consequences."
There was no "failure to understand". This narrative that Afghanistan was a well-intentioned strategic/tactical failure is utterly misleading. The dynamic reality was very clear to every one involved (who cared to know), from servicepeople to 4-star generals, but the military's culture of careerism and corruption prevented these truths from being publicly acknowledged [1].
I’ve been writing and writing on abstract ideas regarding theories of values (i.e. axiologies) since 2018 or so. Some people find my essays/blogposts interesting and become followers of sorts. (Most find them incredibly wordy and roundaboutly.)
I visited India in Dec 2020, so here's my personal take on this based on what I saw. The first lockdown in India was very severe and it basically made the second lockdown pretty unpopular in the business community, at least initially. The dithering contributed to even bigger second wave.
The reasons behind the lull between the first and the second waves were not entirely clear, and some people assumed that the herd immunity is being reached. Combined with the desire to return to normalcy after a harsh lockdown, it falsely assured people that the worst was behind them. This created the perfect conditions for a bigger second wave.
Finally, the state and every petty official was intoxicated by the powers they weilded during the first lockdown, and they forgot that with great power comes the great responsibility. They unnecessarily focused on tiny things such as fining people Rs. 500 at the traffic lights, while not really understanding the new information on how virus spreads, what are the best ways to tackle transmission and so on. People should have been given the liberty to be outdoors with proper face covering when there was good airflow. They shpuld have known that meeting indoors with poor airflow was the biggest threat. This wasn't communicated properly.
Some government officials did take decisions proactively to save their own district. For example, see here
I seriously got into computing in 1979, working for the Microbiology Department at Queen Elizabeth College, University of London, using Research Machines 380Zs, equipped with both 8 and 5.25 inch floppy drives. Here are a few of my observations on the beasts:
- They required quite a lot of strength to open and particularly to close - some of our students were scared they were going to break them (and the cost a lot back then) because of the force needed.
- One student did the classic "remove disk from envelope" thing where they took the actual mylar disc out of the floppy container. He may have been taking the piss, but if so he lost out, as we made students pay for the disks.
- Somewhat unrelated - when I was working in the Netherlands in the 90s, I noticed that supermarkets in Utrecht, a big university town, had floppy disk dispensers in supermarkets - students put in a guilder or whatever, and got a 3.5 inch floppy they could submit their coursework on.
- They were incredibly noisy - the servos were banging away like mad, particularly if you were doing anything database-like, which I mostly was.
- They were horribly unreliable - we used to have to keep sending ours back to RML in Oxford to get them recalibrated or replaced every few months.
Still, all in all they were a million times better than my own personal computer at the time - a Dragon32 with a cassette deck for storage!
1. A Common-Sense Guide to Data Structure and Algorithms from PragProg Bookshelf. Written in a very approachable manner with very good code. The best for self-learners.
2. Algorithms by Dasgupta, Papadimitriou, Vazirani (DPV). Very short and concise book- extremely well-written with a personality. Requires basic CS math.
3. Algorithm Design Manual by Skeina. Extremely approachable as well. Has 'battle stories' of algorithm usage. Good for self-learners. Links to problems in Leetcode is given.
4. CLRS is of course nice for a mathematically rigorous study.