throwaway283719

12 ms·

61.
by throwaway283719 12y ago
Hyperbolic geometry is the geometry of surfaces and spaces that aren't flat. Think of a 2D surface which is curved like a saddle. A triangle drawn on this surface will have angles that add up to less than 180 degrees. Ergodic theory is
62.
by throwaway283719 12y ago
> There is also a reason why FX is quoted to 4 decimal places while equities are to 2, sometimes 3 for penny stocks. Isn't the reason that most FX rates are O(1) (eg EURUSD is about 1.34, cable is about 1.7) whereas most stocks are
63.
by throwaway283719 12y ago
I'm a quant trader working at a hedge fund. I write a lot of code, but not in the same way that I think most people here think about code. A lot of it is hacky Matlab scripts to test some new research idea. Some of it is hand-crafted C
64.
by throwaway283719 12y ago
To mathematicians, the two are kind of interchangeable. I suppose "cartesian product" is a bit more specific, as "cross product" is also used to mean the vector cross product, which is different.
65.
by throwaway283719 12y ago
I think it would be more convincing if it was on her blog and not on the Salary Fairy site.
66.
by throwaway283719 12y ago
Is this just advertising copy?
67.
by throwaway283719 12y ago
Just remember that when you say "someone wants to buy a number of shares at a quoted price" what you really mean is "a giant investment bank or hedge fund with some privileged information about a stock wants to
68.
by throwaway283719 12y ago
I'm glad you brought this up, because this kind of thing happens precisely never on a financial exchange. If you go to a store, the store owner sees you take your apples up to the counter, and so he can theoretically change his price
69.
by throwaway283719 12y ago
I basically agree with what you're saying, but I think there's another point to make - market making is simply not as profitable as it once was. I've seen estimates that the entire high frequency trading industry made $1 bill
70.
by throwaway283719 12y ago
Here is our point of disagreement, then - I think that this is exactly how markets are supposed to work (in the presence of multiple exchanges). The job of a market maker is to supply liquidity at a price/risk tradeoff that is reason
71.
by throwaway283719 12y ago
It's empirically not true that "whomever has the closest connection always wins and everyone else always loses" as is evidenced by the fact that there are multiple competing market makers who are all profitable. Arguments of
72.
by throwaway283719 12y ago
Yes, I think that's a fair summary. I don't know much about contract law, but it may be interesting to know that a resting order on exchange, with a set price and size, is called a quote . The terminology offer is used in finan
73.
by throwaway283719 12y ago
Right, and maybe one day the market will work that way. But (a) what we have at the moment is still a lot better than what we had before - incremental progress! (b) it's not at all obvious (to me) that discrete time steps would be bett
74.
by throwaway283719 12y ago
If you want a reasonably efficient market, you need some participants to have close to perfect information. There is no market anywhere in the world that is 100% efficient, because the costs of getting to efficiency are prohibitively
75.
by throwaway283719 12y ago
What's great is that we don't have to engage in thought experiments about what would happen if we didn't have trading activity with fast computers on a millisecond scale - we can just look back to any time before the 1990s, w
76.
by throwaway283719 12y ago
What is happening here is really quite simple, and doesn't deserve an entire blog post. There are two exchanges, A and B, and a market maker Jill is quoting (say) 10,000 shares on each of those two exchanges for $17. Big institutional
77.
by throwaway283719 12y ago
Well, sure, but the question is how you do "123 * 456". In binary you have the multiplication 111001000 x 1111011 and the traditional grade-school algorithm looks something like this 111001000 11100
78.
by throwaway283719 12y ago
This is essentially what The Economist did. It results in the 'center of mass' being in the northern hemisphere, somewhere near Greenland, because the two biggest economies are both in the hemisphere but at opposite longitudes.
79.
by throwaway283719 12y ago
He claims to have been following this diet for three months whilst maintaining the same weight, and only started seeing a drop in his weight after starting to fast for one day a week (standard sample size disclaimer etc etc).
80.
by throwaway283719 12y ago
You'll note that this isn't presented as a medical study. It's presented exactly as you describe it - an experiment with a sample size of one. No one is telling you to follow this advice. This is one guy saying "Hey, her
81.
by throwaway283719 12y ago
Is there something wrong with making money? If we always settled for "good enough" we wouldn't have half of the nice things we have today, and the potential to make lots of money is a great way of motivating people to push be
82.
by throwaway283719 12y ago
This started off seeming like it might be a promising article, but by the end it becomes clear that it's just terrible clickbait / blogspam. The story seems to be "people use phones and social media more now than in 2004, one
83.
by throwaway283719 12y ago
It reminds me of two other neat problems - 1. Imagine a band stretched taught around the diameter of the earth (which, for the purposes of this question, is a smooth sphere). Now imagine that the band is raised one metre from the ground at
84.
by throwaway283719 12y ago
Meh, it's mathematically deterministic. In reality there is always error (modelling error, measurement error, simulation error) which means that chaotic systems are effectively random on long time scales, even though they are techni
85.
by throwaway283719 12y ago
The tl;dr seems to be that "pinkmeth.com" is a revenge porn site (who are also being sued) and that the Tor Project is being sued because they "knowingly assist sites such as pinkmeth.com".
86.
by throwaway283719 12y ago
Interesting thing about the double pendulum - it is very difficult to get the numerical integration correct, even using very high order integrators like RK4. The simple Euler integrator used here has no hope of getting it right (not a cri
87.
by throwaway283719 12y ago
Yes, the exchange fees are astronomical. It looks like the spread if you wanted to trade 10BTC is around $2 (just looking at the last hour or so of data). On BitStamp the exchange fee is 0.2% (at minimum - can be higher) so trading 10BTC tw
88.
by throwaway283719 12y ago
Well, a big part of the sparsity of the order book is that the tick size is tiny for a market this immature. Take the USD/JPY rate for example, which moves in ticks of 0.01 and is currently sitting at 101.83, so the tick size is 0.0098
89.
by throwaway283719 12y ago
I was lucky enough to have Tim Gowers as a lecturer in my first term of university (hmm... 2002) when he gave a lecture course introducing number theory, set theory, combinatorics and axiomatic construction of number systems. It was intoxic
90.
by throwaway283719 12y ago
This is fake. The pictures is of a baby kangaroo. The story is from NewsHound, a fake news site. http://www.snopes.com/inboxer/hoaxes/dinosaurclone.asp

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