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| bio | website | |
|---|---|---|
| location | ||
| age | 36 | |
| visits | member for | 1 year, 8 months |
| seen | May 9 '12 at 2:58 | |
| stats | profile views | 138 |
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Oct 7 |
awarded | Nice Question |
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Aug 30 |
awarded | Yearling |
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Dec 20 |
comment |
Algorithm for scrolling through different orbits in a permutation group @JoelCohen, you are slightly off on your description of $C_\pi$. Specifically, $C_\pi$ also contains those permutations which map equal-sized cycles in $\pi$ to each other. For example, the centralizer of $(1,2)(3,4)$ in $S_4$ contains $(1,3)(2,4)$. I believe this does give you a full list of generators of $C_\pi$ -- 1) cycles in $\pi$, 2) permutations of the fixed points of $\pi$, and 3) order-preserving swaps of the cycles of a given size in $\pi$. I might be missing something though regarding more complicated actions within each cycle of a given size. |
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Dec 16 |
answered | Expectation of function of random variable? |
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Dec 15 |
comment |
Problem about the sum of independent exponential variable i.i.d., centered and has variance 1. The results then follow from the Central Limit Theorem. Of course, this is an approximation that only holds for large $n$... |
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Dec 9 |
answered | Theorem for a $2$-dimensional (easy) integral with variable boundary |
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Nov 29 |
comment |
How is a Halton sequence related to a Latin hypercube? Another drawback of both techniques is whenever you want to look at multi-point correlations -- both techniques don't let the points cluster as much as a truly random selection would. I believe the Halton sequence does better. |
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Nov 15 |
comment |
Planar kelvin problem I think you got the maximal side length wrong. If the side of the hexagon is $s$, the area is $A = 3\sqrt{3}s^2/2$, so the maximal sidelength is $\sqrt{2A/3\sqrt{3}}$. |
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Nov 15 |
answered | Exciting games and material to motivate children to math |
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Nov 15 |
answered | A subtle modification to the $t$ distribution |
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Nov 8 |
answered | $\sin(A)$, where $A$ is a matrix |
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Nov 7 |
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A function of two functions that loses dependence on an argument Formally, $h$ does require $u$, as the product on the right hand side is undefined when $u=0$. |
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Nov 6 |
comment |
Solve $\displaystyle\int_{0}^a \left(3^{\frac{1}{3} \left( x^3 - 3x \right) }-1\right)\, dx = 0$ using elementary methods Are you trying to solve for $a$? In that case the only answer is $a=0$, since $3^z$ is positive for all real $z$. |
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Nov 4 |
comment |
Probability question: optimal strategy @RossMillikan: That's an unstable equilibrium, as each is indifferent between firing at time $x^*$ and not firing, knowing that the other one will. |
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Nov 4 |
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Probability question: optimal strategy Ross, there is one issue -- if A does not fire at this time $x^*$, B doesn't know what A's $\Delta t$ is, so he can't fire at $x^* + \Delta t/2$. This is why I think both adopt a mixed strategy. |
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Nov 4 |
comment |
Probability question: optimal strategy My suspicion is that the correct answer is a mixed strategy. Each has some probability distribution of when they will shoot given that the other has not yet shot. Now how to determine said distribution... I'm still thinking about it. |
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Nov 4 |
answered | Probability of defeating enemy (info on distributions added) |
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Nov 4 |
comment |
Which is the primary source of the Conway base 13 function? Have you considered emailing John Conway? He could probably point you to the paper where he defined it. He's at Princeton, check the math department webpage. |
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Nov 4 |
comment |
Find a best 4-tuple which fulfils a variable boolean formula This looks sort of like a quadratic programming problem. You might want to look up "Quadratic Programming" on Wikipedia. |
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Nov 4 |
revised |
Find a best 4-tuple which fulfils a variable boolean formula edited tags |
