User Alex Nelson - Mathematics Stack Exchange

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visits	member for	1 year
	seen	May 14 at 13:47
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	689 reputation	bio	website	code.google.com/p/notebk	visits	member for	1 year
18 badges		location			seen	May 14 at 13:47

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Intuition behind the difference between derived sets and closed sets?

apr 22 at 19:57 Brian M. Scott 154k

5

14

votes

3

answers

260

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A relationship between matrices, bernoulli polynomials, and binomial coefficients

linear-algebra number-theory binomial-coefficients bernoulli-numbers

dec 26 at 21:19 oen 7,443

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answer

354

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Can the real and imaginary parts of $\dfrac{\sin z}z$ be simplified?

complex-analysis trigonometry hyperbolic-functions

dec 1 at 1:12 Antonio Vargas 6,690

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votes

1

answer

133

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A book of probability puzzles

probability reference-request recreational-mathematics

nov 25 at 0:52 Frxstrem 174

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answers

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Showing that $\int\limits_{-a}^a \frac{f(x)}{1+e^{x}} \mathrm dx = \int\limits_0^a f(x) \mathrm dx$, when $f$ is even

homework calculus real-analysis integration

oct 21 at 3:06 user17762 76.1k

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votes

3

answers

1

kviews

GRE Math Subject Test

advice

oct 21 at 0:55 KReiser 1,620

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votes

3

answers

161

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Lie algebra action from Lie group action: coordinates

homework representation-theory lie-algebras manifolds

oct 22 at 23:09 user9610 43

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votes

1

answer

1

kviews

What do the eigenvectors of an adjacency matrix tell us?

graph-theory eigenvectors spectral-graph-theory

jul 10 at 16:06 tskuzzy 559

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votes

3

answers

279

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What are the epimorphisms in the category of Hausdorff spaces?

general-topology category-theory

oct 18 at 4:06 Shawn Henry 146

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9

votes

4

answers

265

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How to evaluate this integral $\int_{-\infty}^{+\infty}\frac{x^2e^x}{(1+e^x)^2}dx$?

complex-analysis improper-integrals

jan 2 at 0:15 Community♦ 1

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3

votes

2

answers

98

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Unitary representation of $SO(3)$

representation-theory lie-groups

oct 10 at 14:17 AlbertH 3,542

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23

votes

5

answers

2

kviews

Is the set of all valid C++ programs countably infinite?

infinity regular-language

apr 16 at 0:51 Cameron Buie 27.5k

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20

answers

2

kviews

Your favourite maths puzzles

soft-question big-list puzzle

aug 23 at 13:52 Mad Scientist 129

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28

answers

2

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Classical texts that should not be missing from any shelf

reference-request soft-question big-list

jan 15 '12 at 15:08 Zach Langley 605

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answers

422

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What are the math challenges websites?

reference-request big-list

sep 18 at 20:15 rrampage 192

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2

answers

792

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Topology of matrices

general-topology matrices compactness connectedness

sep 17 at 6:15 Aleš Bizjak 743

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votes

2

answers

264

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Literature on Mathematical Problem Posing

reference-request recreational-mathematics problem-solving

jan 27 at 23:09 B.D 2,111

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votes

3

answers

505

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Intuition behind Snake Lemma

abstract-algebra algebraic-topology intuition homological-algebra abelian-categories

sep 30 at 23:15 Norbert 20k

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5

votes

2

answers

130

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Is $\mathbb{Z}[\sqrt{2},\sqrt{3}]$ flat over $\mathbb{Z}[\sqrt{2}]$?

homework commutative-algebra

jul 24 at 5:40 Matt E 57.8k

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2

votes

1

answer

141

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Mathematics behind a programming puzzle

probability probability-theory

jul 16 at 20:53 André Nicolas 161k

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1

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148

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Sylow 2-subgroups of the group $\mathrm{PSL}(2,q)$

group-theory

jul 13 at 16:51 Geoff Robinson 9,657

4

votes

1

answer

203

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A particular (functional) determinant calculation

linear-algebra functional-analysis representation-theory physics determinant

jul 3 at 23:07 oen 7,443

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2

kviews

Open problems in General Relativity

big-list general-relativity

aug 20 at 20:50 Community♦ 1

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answer

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How does the method of Lagrange multipliers fail (in classical field theories with local constraints)?

functional-analysis optimization multivariable-calculus examples-counterexamples

mar 10 '11 at 6:43 Simon 715

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votes

2

answers

69

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How many transvections are in a maximal unipotent subgroup of a general linear group?

group-theory finite-groups

jun 19 '12 at 23:34 Jack Schmidt 20.1k

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votes

1

answer

259

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Heat equation in bounded domain

functional-analysis pde

jun 18 '12 at 12:44 Willie Wong♦ 30.7k

Alex Nelson

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