User Hardy - Mathematics Stack Exchange

bio	website	google.com
	location	Melbourne, Australia
	age	30
visits	member for	1 year, 3 months
	seen	May 18 at 18:49
stats	profile views	489

	1,190 reputation	bio	website	google.com	visits	member for	1 year, 3 months
1624 badges		location	Melbourne, Australia		seen	May 18 at 18:49

26

44

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6

answers

2

kviews

What made you choose your research field?

soft-question advice

dec 12 at 5:14 Kyle 1,485

1

2

votes

3

answers

2

kviews

lim sup and lim inf of sequence of sets.

elementary-set-theory limsup

apr 5 '12 at 7:52 Martin Sleziak 20.3k

2

votes

3

answers

1

kviews

Complex vector spaces

linear-algebra vector-spaces

jan 29 '12 at 1:32 emiliocba 458

1

vote

1

answer

800

views

Proof of Intersection of Inverse Images of functions

elementary-set-theory proof-writing

feb 23 '12 at 6:08 Community♦ 1

2

votes

3

answers

716

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Convergence of $\sum _{n=1}^{\infty }\left\{ 1-n\log \dfrac {2n+1} {2n-1}\right\} $

sequences-and-series limit convergence

jun 15 '12 at 10:04 Chris's wise sister 11.5k

1

4

votes

0

answers

452

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Characteristic functions based proof problem.

real-analysis measure-theory characteristic-functions

oct 29 at 22:11 Davide Giraudo 56.2k

1

3

votes

1

answer

451

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dual space is a vector space

vector-spaces

jan 29 at 11:59 user60088 1

1

vote

1

answer

430

views

How to find the upper bound for this series

real-analysis sequences-and-series

feb 28 '12 at 20:01 André Nicolas 161k

2

7

votes

5

answers

401

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what is Prime Gaps relationship with number 6?

number-theory prime-numbers

mar 7 '12 at 18:57 Ernie 21

1

3

votes

1

answer

398

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Finding the joint density of sums of normally distributed random variables.

probability probability-distributions

oct 26 at 20:19 Did 103k

0

votes

1

answer

378

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Finite disjoint unions of intervals?

elementary-set-theory

feb 11 '12 at 7:14 Brian M. Scott 154k

5

votes

1

answer

373

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Proof of a theorem of Cauchy's on the convergence of an infinite product

real-analysis sequences-and-series convergence proof-strategy

mar 12 '12 at 22:13 Aryabhata 47.6k

1

vote

1

answer

364

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Finding determinant of an infinite matrix

linear-algebra matrices

mar 7 '12 at 8:25 late_learner 1,560

2

votes

1

answer

358

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primitive roots of unity

abstract-algebra number-theory complex-analysis prime-numbers complex-numbers

feb 20 '12 at 19:22 Hardy 1,190

2

votes

3

answers

343

views

Can vectors be inverted?

linear-algebra

oct 7 at 0:54 adam W 3,180

1

vote

1

answer

342

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Example that a measurable function $f$ on $[1,\infty )$ can be integrable when $\sum _{n=1}^{\infty }\int_{n}^{n+1}f$ diverges.

real-analysis sequences-and-series measure-theory integration

sep 15 at 20:14 Hardy 1,190

1

0

votes

2

answers

324

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Invertibility of a function and left/right inverses

functions elementary-set-theory proof-writing

feb 5 '12 at 16:04 Klaus 1,061

1

3

votes

1

answer

321

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Mathematics From Futurama

differential-equations puzzle recreational-mathematics mathematical-modeling

mar 19 '12 at 18:58 alex.jordan 8,814

4

8

votes

4

answers

297

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Trying to show $1-\dfrac {1} {2} -\dfrac {1} {4}+\dfrac {1} {3}-\dfrac {1} {6}-\dfrac {1} {8}+\dfrac {1} {5}-\cdots =\dfrac {1} {2}\log 2$

real-analysis combinatorics sequences-and-series

mar 11 '12 at 21:19 Hardy 1,190

2

votes

2

answers

297

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Wanted: example of an increasing sequence of $\sigma$-fields whose union is not a $\sigma$-field [duplicate]

elementary-set-theory

feb 11 '12 at 23:36 Brian M. Scott 154k

1

3

votes

4

answers

295

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Show that this limit is equal to $\liminf a_{n}^{1/n}$ for positive terms.

real-analysis sequences-and-series limit

jun 22 '12 at 8:21 Amihai Zivan 1,083

3

7

votes

2

answers

287

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convergence of $\sum \limits_{n=1}^{\infty }\left\{ \dfrac {1\cdot3 \cdots (2n-1)} {2\cdot 4\cdots (2n)}\cdot \dfrac {4n+3} {2n+2}\right\} ^{2}$

real-analysis sequences-and-series limit convergence

mar 10 '12 at 4:00 Quixotic 7,930

0

votes

2

answers

287

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Can a Vector space have subspaces of same dimension over different fields?

linear-algebra vector-spaces

feb 8 '12 at 20:23 Arturo Magidin 158k

3

votes

2

answers

286

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Behaviour of $\sum u_{n}\cos(n\theta +a) $ when $\theta\over\pi$ is rational and when irrational

real-analysis sequences-and-series limit convergence

mar 27 '12 at 8:35 Julián Aguirre 14.6k

0

votes

1

answer

282

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Please confirm my lim sup and lim inf of sets answers

elementary-set-theory

feb 11 '12 at 6:51 Henno Brandsma 9,732

4

votes

2

answers

277

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Evaluating the sum after reordering an infinite series $1-\dfrac {1} {2}+\dfrac {1} {3}-\dfrac {1} {4}+\ldots $

real-analysis sequences-and-series

jun 19 '12 at 15:48 Chris's wise sister 11.5k

4

votes

2

answers

269

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Absolute and uniform convergence of $\sum _{n=1}^{n=\infty }2^{n}\sin \frac {1} {3^{n}z}$

real-analysis sequences-and-series limit convergence

mar 23 '12 at 22:03 Brian M. Scott 154k

1

vote

2

answers

264

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Proving that if $a\mathbf{x}=\mathbf{0}$ then $a=0$ or $\mathbf{x}=\mathbf{0}$

linear-algebra abstract-algebra vector-spaces

jan 29 '12 at 0:38 Arturo Magidin 158k

1

4

votes

3

answers

263

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showing almost equal function are actually equal

real-analysis measure-theory

aug 1 at 23:14 ncmathsadist 17.2k

2

votes

2

answers

260

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Show $\sum _{n=1}^{\infty }f_{n}\cos \left( n\theta \right) $ converges

real-analysis sequences-and-series

feb 27 '12 at 20:16 user10676 2,240

Hardy

105 Questions