pierrealexandre

There is some interesting research regarding the optimal tick size (by instrument), eg https://arxiv.org/abs/1207.6325

No, it does not sit at the same 1-tick spread all day. Typically for these tickers the 1-tick spread transitions very quickly to the 1-tick spread above or below (each individual market is going to be 2-tick wide for a very small amount of time at each tick transition, much less than 1 second).

If I understand Table 1 correctly, it shows that with ICC a block size of 8 with 4000x4000 matrices gives roughly a speedup factor of 2 (~10.53 / 6.38). The unit is not clearly stated but it looks like a bigger number means a better "performance" ie a faster program.

The article provides historical context and a framework to think about the question. I think it does a better job answering the question than your last 2 paragraphs.

Actually, replace 90 by 91 (100 / 1.1), and 35 by 38.5 (100/1.1^10)

You don't "specify a duration" for the valuation: an infinite duration is baked in the valuation itself through the time value of money. If the annual interest rate is 10%, 100$ in 1 year is worth 90$ today, 100$ in 10 years is worth about 35$ today and so on. Of course, in the case of company valuations, you have to also account for the uncertainty (both on the upside and downside) of the future cash flows.

Isn't the phenomenon you describe extreme price elasticity rather than inelasticity?

Also, any source for your assertion about the effect of rent control on rents in NYC? I'm very interested in this if you have it.

Are you aware of the distionction between market orders and limit orders?

HFTs by themselves can provide liquidity (like any other investor), namely by entering a limit order in the order book. They can also by themselves narrow the bid-ask spread, namely by entering a limit order at a price more competitive than the current first limit.

Of course, someone else has to send a market order to the exchange for a trade to execute.

> With almost half the world’s Internet-connected population using the service, the company is facing the immutable law of large numbers and simply can’t keep adding users at its previously torrid rate.

Pretty sure this journalist does not have a correct understanding of what the law of large numbers is. Very infuriating, even though I tend to find Businessweek's articles to be usually quite informative.

In my opinion the following paper is a good and accesible primer on econophysics: JP Bouchaud - The (unfortunate) complexity of the economy http://arxiv.org/abs/0904.0805

This is the perfect cheatsheet for a question I got during an interview at a major GPU company : "You write an OpenGL program displaying a colourful object, but you get a black screen when you launch it. What could have gone wrong in your code ?". I painfully thought about 3 or 4 of them and am now deeply embarrassed by my lack of imagination.

The feature "display my position" is available in Google Maps. It is not when I use Safari 4.0.

Paris, France

In my opinion, it shows the absurdity of tax competition among states, not of tax hikes themselves.

I would rather read what makes Paris different from NYC in your opinion. It would make for a much more interesting comment.

Most of the quants have to code themselves. Some of them have PhD/MS from the best CS departments. Very few of them have an army of "minions hacking for [them]".

That doesn't automatically mean they develop superior sofftware development skills, but I think your comment misrepresents the reality.

I may be totally mistaken, but doesn't the result depend on X and Y unit (or alternatively on the standard dev of the gaussian) ?

Yes, I don't get this quote neither. I honestly am not sure how to interpret it. Does his lack of answer show that he has no clue about this million-node botnet thing ? Or that he does not want to talk about such a sensitive matter ?

Moreover, is any 3* general supposed to know what this is all about ? Are we talking about a specific general well versed in these matters ?

I submitted this story though, because I have not heard about this worm before and I found the speculations about the final goal of this attack rather surprising.